Blood chemistry (Dogs and Cats)

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BLOOD CHEMISTRY

Jessica C. Largado

What is blood chemistry?

Blood chemistry is the chemical composition of the blood.

ALANINE AMINOTRANSFERASE

• ALT is an enzyme located in the cytosol of many cell types, with a relatively high concentration in liver and lesser quantities in the kidneys, heart, skeletal muscle, and RBCs.

• more specific indicator of liver damage than is AST• not generally regarded as significant unless they

are 2–3 times normal

INDICATIONSSuspected hepatic disease

CONTRAINDICATIONSNone

POTENTIAL COMPLICATIONSNone

CLIENT EDUCATIONNone

BODY SYSTEMS ASSESSED Hepatobiliary Musculoskeletal

SAMPLE COLLECTION0.5–2.0 mL of venous blood

HANDLING A plain red-top tube or serum-separator tube EDTA, sodium heparin, or lithium heparin are acceptable anticoagulants. Separate refrigerated serum or plasma from cells within 2 days.STORAGE

Refrigerate or freeze serum or plasma for long-term storage.STABILITY Room temperature: 1 day Refrigerated (2◦–8◦C): 1 week

Frozen (−20◦C): >1 weekPROTOCOL

Species Normal Range

Dog 18-86 IU/L

Cat 29-145 IU/L

Drugs That May Alter Results or InterpretationDrugs That Interfere With Test Methodology

• Metronidazole may artifactually depress AST activity as determinedby reduced NADH-coupled analytical methods. Interference is from similarity in absorbance peaks of NADH (340 nm) and metronidazole(322 nm).• AST activity can be decreased by drugs (e.g., cephalosporin,

cyclosporine, isoniazide) that impair activation of vitamin B6 to pyridoxal 5-phosphate (P5P). This effect can be avoided if P5P is added as an assay cofactor.

Drugs That May Alter Results or InterpretationDrugs That Alter Physiology

• Corticosteroids may increase ALT by possible induction or cell injury (steroid hepatopathy).

• Phenobarbital treatment may increase ALT by induction or cell injury.• ALT activity can be increased by a variety of hepatotoxic drugs (e.g.,erythromycin, rifampin, sulfonamides, acetaminophen, caparsolate).

Disorders That May Alter Results• Hemolysis can cause a mild increase in ALT activity.• Lipemia can cause an artifactual increase in ALT activity.• Low vitamin B6 levels may decrease ALT activity, as this is an essentialcofactor for the enzyme

Collection Techniques or Handling That May Alter Results• Hemolysis or severe lipemia

Influence of SignalmentSpecies

NoneBreed

NoneAge

NoneGender

NonePregnancy

High values Low values

Hepatocellular injury or leakage Hepatic atrophy

Inflammation (hepatitis) Decreased P5P levels

Toxin or drug reactions

Corticosteroid hepatopathy

Hepatic lipidosis

Hypoxia

Causes of Abnormal Findings

LIMITATIONS OF THE TEST• It is relatively specific and sensitive for liver damage, but ALT activitymay be normal or only slightly increased with significant chronicdisease associated with decreased hepatic mass.

Sensitivity, Specificity, and Positive and Negative PredictiveValues• N/A

ANCILLARY TESTS• AST may be measured concurrently to help confirm hepatocellular

injury.• Assaying creatine kinase levels may be useful to rule in or rule out

muscle necrosis as a possible cause for an increased ALT level.• Assay alkaline phosphatase or GGT level to detect any cholestatic

component of liver disease.• Assay serum bile acids or plasma ammonia levels to assess hepatic

function.

ALBUMIN

• 75%–80% of the oncotic pressure of plasma.• Important carrier protein for free fatty acids,

Ca2+, Mg2+, bile acids, unconjugated bilirubin, thyroxine, and certain drugs

• direct correlation between albumin turnover rate and body size

ALBUMINIndications• To assess hydration status• To evaluate patients with anemia, cavity effusions, liver disease, renal disease,

weight loss, and/or edemaCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Gastrointestinal• Hepatobiliary• Renal or urologic

ALBUMINSAMPLECOLLECTION• 0.5–2.0 mL of venous bloodHANDLING• Plain red-top tube or serum-separator tube• Sodium heparin, or lithium heparin anticoagulant also acceptableSTORAGE• Store at room temperature for short-term use.• Refrigerate for up to 1 month.• Freeze for the long term.STABILITY• Room temperature: 1 week• Refrigerated (2◦–8◦C): 1 month• Frozen (−18◦C): >1 monthPROTOCOL• None

ALBUMIN

Species Normal Range

Dog 2.8-4.0 g/dL(28-40 g/L)

Cat 2.4-3.9 g/dL

ALBUMININTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Acetylsalicylic acid at higher than therapeutic doses—decreased levels

Drugs That Alter Physiology• High-dose glucocorticoids can cause a slight increase.• Testosterone, estrogen, or growth hormone may cause mild increases.

Disorders That May Alter Results• Hemolysis or hemoglobinemia can cause false increases.• Marked lipemia or hypertriglyceridemia can cause false decreases.• With severe hypoalbuminemia (i.e., <1 g/dL), BCG may bind to globulins,

causing a falsely elevated albumin concentration.

ALBUMININTERFERING FACTORSCollection Techniques or Handling That May Alter Results• Marked hemolysis can cause false increases.• Failure to fast a patient may result in lipemia.

ALBUMINInfluence of SignalmentSpecies

NoneBreed

NoneAge

Puppies, kittens, calves, and foals may have lower albumin concentrations than adult animals.

In adult animals, a slight decrease in albumin occurs with advancingage.Gender

NonePregnancy

Decreases occur with pregnancy and lactation.

ALBUMINHigh Values Low values

Hemoconcentration due to dehydration Decreased production Hepatic insufficiency or failure Intestinal malabsorption Exocrine pancreatic insufficiency InflammationIncreased loss Blood loss Protein-losing nephropathy Glomerulonephritis (immune mediated or congenital) Amyloidosis Protein-losing enteropathy Small intestinal mucosal disease (inflammation, neoplasia) Lymphangiectasia Intestinal hemorrhage (intestinal parasites) Protein-losing dermatopathy: burns, generalized exudative skin disease Vasculitis

ALBUMINHigh Values Low values

Hemodilution Excessive IV fluid administration SIADH Edematous disorders: congestive heart failure

ALBUMINANCILLARY TESTS• Liver enzymes and bile acids• Total protein and globulins• Urinalysis• Urine protein/creatinine ratio

ALKALINE PHOSPHATASE• Variable forms of ALP (isoenzymes) are produced in different

tissues and with different inducing agents• most common isoenzymes found in serum of dogs and cats

are the liver isoenzyme (increased in cholestasis, etc.), the bone isoenzyme (increased with bone remodeling), and, in dogs only, a corticosteroid-induced isoenzyme (produced in the liver).

ALKALINE PHOSPHATASEINDICATIONS• Suspected hepatic or biliary disease• Suspected Cushing’s syndromeCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Hepatobiliary• Musculoskeletal• Endocrine or metabolic

ALKALINE PHOSPHATASESAMPLECOLLECTION• 0.5–2 mL of venous bloodHANDLING• Collect into a plain red-top tube or serum-separator tube.STORAGE• Refrigerate for short-term storage, and freeze for long-term storage.STABILITY• Room temperature or refrigerated: 1 week• Frozen (−20◦C): 2 monthsPROTOCOL• None

ALKALINE PHOSPHATASESpecies Normal Range

Dog 12-121 IU/L

Cat 10-72 IU/L

ALKALINE PHOSPHATASEINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• In dogs, any corticosteroid treatment (even topical or ophthalmic treatments)

increases ALP levels. Effects may persist for weeks after discontinuation of the drug, particularly with “depo”-type formulations.

• Anticonvulsants and barbiturates (phenobarbital, phenytoin, primidone) may also cause ALP increases.

Disorders That May Alter Results• NoneCollection Techniques or Handling That May Alter Results• None

ALKALINE PHOSPHATASEInfluence of SignalmentSpecies• ALP is relatively insensitive for cholestasis in cats.• Dogs are unique in producing a corticosteroid isoenzyme of ALP (CALP) in response to

corticosteroid treatment or increased endogenous corticosteroids.Breed• Some families of Siberian huskies and Scottish terriers have ALP levels 1.5- to 17-fold

normal and no evidence of hepatic abnormalities or increased cortisol concentration.Age• Young, rapidly growing animals (<12–15 months) commonly have increased serum ALP

levels (bone isoenzyme).• Geriatric dogs often have elevated ALP because of hepatic nodular hyperplasia.Gender• NonePregnancy• Pregnant, nursing animals may have increased ALP (bone remodeling, etc.).

ALKALINE PHOSPHATASELIMITATIONS OF THE TESTSensitivity, Specificity, and Positive and Negative Predictive Values For cholestatic disease in dogs:• Sensitivity, 96%• Positive predictive value, 61%• Negative predictive value, 94%• Relatively insensitive for cholestasis in the cat.

ALKALINE PHOSPHATASEHigh values Low values

Liver ALPCorticosteroid treatment or increasedendogenous corticosteroids (early)Corticosteroid hepatopathy (cholestasis)Hepatic nodular hyperplasiaHepatic lipidosisCirrhosisHepatitis or cholangiohepatitisGallstonesCholecystitisHepatic or biliary neoplasiaPancreatitisAnticonvulsant therapyHyperthyroidismCopper storage disease

No significance

Bone ALPYoung, growing animalsFracture repair

ALKALINE PHOSPHATASEBone neoplasiaMetabolic bone disease (resorption)HyperthyroidismPregnancyFamilial hyperphosphatemia (Siberianhuskies, Scottish terriers)

Corticosteroid ALP (canine only)HyperadrenocorticismGlucocorticoid therapySevere non-adrenal disease (stress ofdisease causes increasedcortisol secretion)

ALKALINE PHOSPHATASEANCILLARY TESTS• Levamisole-inhibition test and heat-inactivation test to

measure CALP: Levamisole and heat both selectively inhibit noncorticosteroid isoenzymes of ALP.

• Isoenzyme electrophoresis to quantify various ALP enzymes• GGT and/or bilirubin levels to confirm a cholestasis• ALT and AST to detect hepatocellular injury• Urine cortisol/creatinine ratio to screen for

hyperadrenocorticism

AMYLASE• Enzyme that hydrolyzes starch and glycogen• Arises from the pancreas and many other tissues, such as

duodenum, kidney, lung, and spleen • Cleared from the plasma by the kidneys

AMYLASEINDICATIONS• Clinical signs suggestive of canine pancreatitis (vomiting, anorexia, abdominal

pain, icterus)• Nonseptic, inflammatory abdominal exudateCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• Dogs should be fasted for most accurate results.• Clients should know that amylase is a nonspecific test and can be associated with

pancreatitis, as well as disease in other organs such as kidney or intestine.BODY SYSTEMS ASSESSED• Gastrointestinal• Hepatobiliary• Renal and urologic

AMYLASESAMPLECOLLECTION• 1–2 mL of venous blood• Abdominal fluidHANDLING• A red-top tube or serum-separator tube is preferred.• A lithium heparin (green-top) tube is acceptable but not preferred.STORAGE• Refrigerate or freeze.STABILITY• 1 week at room temperature• At least 1 month at 2◦–8◦C (refrigerated)• Years at −20◦C (frozen)PROTOCOL• None

AMYLASESpecies Normal Range

Dog 371-1503 IU/L

Cat 571-1660 IU/L

AMYLASEINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• Drugs that may induce pancreatitis include Glucocorticoids• Antibiotics, such as metronidazole, sulfonamides, and tetracycline• Diuretics, including furosemide and thiazides• Other drugs, such as asparaginase and azothiaprineDisorders That May Alter Results• NoneCollection Techniques or Handling That May Alter Results• None

AMYLASEInfluence of SignalmentSpecies• Elevated amylase can be suggestive of pancreatitis in dogs, but is an• unreliable indicator of pancreatitis in cats.Breed• NoneAge• NoneGender• NonePregnancy• None

AMYLASELIMITATIONS OF THE TEST• Amylase has poor sensitivity and specificity for the diagnosis of

pancreatitis.• Because amylase is produced in nonpancreatic tissues such as the

kidney or intestine, diseases of these tissues may increase amylase activity.

• The level of amylase activity does not correlate with the severity of pancreatitis, and normal amylase levels can be seen in some patients with severe acute pancreatitis.

Sensitivity, Specificity, and Positive and Negative PredictiveValues• N/A

AMYLASE

High Values Low values

Severe dehydration Not significant

Renal disease

Pancreatitis

Intestinal disease

Hepatic disease

Decreased GFR

Urinary tract obstruction

AMYLASEANCILLARY TESTS• Lipase, pancreatic lipase immunoreactivity, or trypsin-like

immunoreactivity for confirmation of pancreatic disease• BUN, creatinine, urinalysis for evaluation of renal function• Liver enzymes• Ultrasound of the pancreas

ASPARTATE AMINOTRANSFERASE

• highest concentration of AST can be found in skeletal muscle, followed by liver and cardiac muscle

INDICATIONS• To test for hepatic disease• To detect muscle injury and necrosisCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Hepatobiliary• Musculoskeletal• Hemic, lymphatic, and immune

SAMPLECOLLECTION• 0.5–2.0 mL of venous bloodHANDLING• Plain red-top tube or serum-separator tube• EDTA, sodium heparin anticoagulant, or lithium heparin anticoagulant are acceptable.• Separate serum or plasma from cells within 8 h at room temperature or within 2 days

at 2◦–8◦C (refrigerated).STORAGE• Refrigerate or freeze serum or plasma for long-term storage.STABILITY• 1 day at room temperature• 1 week at 2◦–8◦C (refrigerated)PROTOCOL• None

ASPARTATE AMINOTRANSFERASESpecies Normal Range

Dog 16–54 IU/L

Cat 12–42 IU/L

ASPARTATE AMINOTRANSFERASEINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Metronidazole may artifactually depress AST activity as determined by NADH-coupled analytic

methods. • AST activity can be decreased by drugs that impair activation of vitamin B6 to pyridoxal 5-

phosphate (P5P) (e.g., cephalosporin, cyclosporine, isoniazide). This effect can be avoided if P5P is added as an assay cofactor.

Drugs That Alter Physiology• AST activity can be increased by a variety of hepatotoxic drugs (e.g., erythromycin, rifampin,

sulfonamides, acetaminophen, caparsolate).• Anticonvulsants may induce enzyme synthesis or possible hepatotoxicity.Disorders That May Alter Results• Marked lipemia may interfere with spectrophotometric assays.• Low vitamin B6 levels (idiopathic or after hemodialysis) may decrease• AST activity, as this vitamin is an essential cofactor of the enzyme.Collection Techniques or Handling That May Alter Results• In vitro hemolysis will increase CK measurements, which might alter interpretation of elevated

Influence of SignalmentSpecies• NoneBreed• NoneAge• Higher levels are seen in neonatal kittens during the first 2 months

of life.Gender• NonePregnancy• None

LIMITATIONS OF THE TEST• Because of wide tissue distribution (muscle, erythrocytes),

AST elevations are not specific for liver injury.• It generally has high sensitivity for liver or muscle damage,

but AST activity may be normal or only slightly increased with significant chronic disease associated with decreased hepatic mass.

ASPARTATE AMINOTRANSFERASEHigh Values Low values

Hepatocellular injury or leakage Hepatic atrophy (as in chroniccongenital portosystemicshunts)

Inflammation (hepatitis) Decreased P5P levels (if notadded to assay

Toxin and drug reactions

Hepatic or biliary neoplasia

Hepatic lipidosis

Hypoxia (anemia, cardiovasculardisease)Pancreatitis

Trauma

Liver flukes

Copper storage disease

Muscle injury and necrosis

Trauma

Overexertion

Myositis

Intravascular hemolysis

Immune-mediated hemolytic anemia

Oxidant damageZincOnionsAcetaminophen (cats)Other oxidants

RBC parasites

In vitro hemolysis (artifact)

Cirrhosis

ANCILLARY TESTS• CK levels to rule in/out muscle necrosis as a possible cause of

an increased AST level• ALT to help confirm hepatocellular injury• ALP or GGT may help detect any cholestatic component of

liver disease.• Serum bile acids or ammonia to assess hepatic function

BILE ACIDS• synthesized in the liver from cholesterol and secreted into

bile, with a pool of BAs being stored in the gallbladder.

BILE ACIDSINDICATIONS• Assessment of hepatic function• Detection of cholestatic disease• Screening for portosystemic shuntCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Cardiovascular• Hepatobiliary

BILE ACIDSSAMPLECOLLECTION• 0.5–2.0 mL of venous bloodHANDLING• The blood sample can be collected into plain red-top tube or serumseparator tube.• Refrigerate for short-term storage, and freeze for long-term storage.STABILITY• Stable for >3 days in refrigerated serum.PROTOCOL• The baseline sample is collected after fasting (8–12 h).• The postprandial sample is collected 2 h after feeding:• Feed a maintenance diet (avoid low-fat, low-protein foods).• Feed at least 2 teaspoons of food to animals weighing <5 kg.• Feed about one-quarter can to larger animals.• Avoid overfeeding, because lipemia can compromise results.• Visually confirm meal consumption.

BILE ACIDSSpecies Normal Range

Dog 0-8 umol/L, fasting 0-30 umol/L, 2h post-prandial

Cat 0-5 umol/L, fasting 0-15 umol/L, 2h postprandial

BILE ACIDSINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Treatment with ursodiol (a synthetic BA) will increase serum BA measurements.Drugs That Alter Physiology• Cholestryamine binds BAs and prevents their resorption, decreasing blood levels.Disorders That May Alter Results• Gallbladder contraction. Spontaneous gallbladder contraction (without feeding) may increase

the fasting BA level. Alternately, incomplete contraction after feeding may result in a lower value than expected.

• Lipemia. Lipemia may increase BA measurement (spectrophotometry).• Ileal disease (or resection) or other malabsorption disorders may decrease BA levels

(decreased absorption).• Small-bowel bacterial overgrowth can alter bacterial processing of BA, decreasing ileal

absorption.Collection Techniques or Handling That May Alter Results• Hemolysis may decrease BA measurement.• Heparin may decrease BA measurement.• If lipid-clearing agents are employed to eliminate lipemia, these may decrease measured BAs.

BILE ACIDSInfluence of SignalmentSpecies• NoneBreed• Terrier breeds, including Yorkshire terriers, shih tzus, Maltese, bichon frises, Tibetan

spaniels, and Havanese, are prone to microvascular dysplasia, which can increase serum BAs.

• Maltese dogs often have elevated postprandial serum BAs in the absence of hepatobiliary disease. An ammonia-tolerance test may be warranted to rule out microvascular dysplasia.

Age• NoneGender• NonePregnancy• None

BILE ACIDSLIMITATIONS OF THE TEST• Not all patients with liver disease have elevated BA.• The level of BA elevation is not diagnostic for the type of liver disease or the

prognosis.• Postprandial BA levels are generally more sensitive than fasting BA for detection of

hepatobiliary disease.Sensitivity, Specificity, and Positive and Negative Predictive Values• Dogs: Serum BA• Postprandial BA, >15 μmol/L• Sensitivity, 82%; specificity, 89%• Fasting BA, >20 μmol/L• Sensitivity, 59%; specificity, 100%• Postprandial BA, >25 μmol/L• Sensitivity, 74%; specificity, 100%

BILE ACIDSSensitivity, Specificity, and Positive and Negative Predictive Values• Cats: Serum BA• Fasting BA, >15 μmol/L• Sensitivity, 54%; specificity, 96%• Postprandial BA, >20 μmol/L• Sensitivity, 100%; specificity, 80%• Dogs: UNSBA + USBA/Creatinine• Specificity, 100%; sensitivity, 61%• Positive predictive value, 100%; negative predictive value, 18%• Cats: UNSBA + USBA/Creatinine• Specificity, 88%; sensitivity, 85%• Positive predictive value, 96%

BILE ACIDSHigh Values Low values

Inflammation (hepatitis and/orcholangiohepatitis)

No clinical significant

Hepatic or biliary neoplasia

Pancreatitis

Gall stones

Hepatic lipidosis

Toxin and/or drug reactions

Cirrhosis

Portosystemic shunt

Hepatic microvascular dysplasia

BILE ACIDSANCILLARY TESTS• ALT and/or AST to evaluate hepatocellular injury• ALP and/or GGT to test for increased values that occur with

cholestatic disease• A test of ammonia level to evaluate hepatic function and

portal circulation, which should be normal in cholestatic disease unless shunting and/or decreased hepatic function are also present

• Albumin and BUN levels may be decreased with loss of hepatic function

BILIRUBIN• yellow pigment produced as a breakdown product of

hemoglobin

BILIRUBININDICATIONS• Suspected hepatobiliary disease• Suspected hemolytic diseaseCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Hemic, lymphatic, and immune• Hepatobiliary

BILIRUBINSAMPLECOLLECTION• 0.5–2.0 mL of venous bloodHANDLING• Collect into plain red-top tube or serum-separator tube.STORAGE• Protect from light.• Refrigerate for short-term storage.• Freeze for long-term storage.STABILITY• Bilirubin levels can decrease up to 50% if exposed to direct sunlight.• Refrigerated (2◦–8◦C): >1 week if protected from light• Frozen (−20◦C): ≈3 monthsPROTOCOL• None

BILIRUBINSpecies Normal Range

Dog 0.1-0.3 mg/dL

Cat 0.1-0.3 mg/dL

BILIRUBININTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Propranolol administration-increase bilirubin measurementsDrugs That Alter Physiology• NoneDisorders That May Alter Results• Hemolysis and Lipemia may artifactually increase values.Collection Techniques or Handling That May Alter Results• Avoid the use of hemolysed samples.• Exposure to ultraviolet light (including sunlight) will decrease

bilirubin levels.

BILIRUBINInfluence of SignalmentSpecies• NoneBreed• NoneAge• NoneGender• NonePregnancy• None

BILIRUBINLIMITATIONS OF THE TEST• Bilirubinuria typically precedes hyperbilirubinemia.• Bilirubin is a relatively insensitive test for cholestasis. Enzyme

increases (ALP, GGT) are typically more sensitive indicators of cholestatic disease.

BILIRUBINHigh Values Low values

Prehepatic Accelerated RBC destruction (hemolysis)Immune-mediated hemolytic anemiaAcetaminophenZinc toxicityRBC parasitesHypophosphatemiaTransfusion reactionsMicroangiopathic anemiaInternal hemorrhage

No significant

HepaticHepatitis or cholangiohepatitisToxin or drug reactionsHepatic neoplasiaCorticosteroid hepatopathyHepatic lipidosis

BILIRUBINHigh Values Low values

CirrhosisChronic portosystemic shunt (withthe hepatic atrophy)Copper storage diseasePosthepaticGallbladder diseaseBile peritonitisBiliary neoplasiaCholecystitisPancreatitis

BILIRUBINANCILLARY TESTS• CBC for evidence of hemolytic disease (e. g., anemia,

spherocytosis)• Testing of ALT to evaluate hepatocellular injury• Evaluation of ALP and/or GGT to look for cholestatic disease• Evaluation of ammonia or bile acids• Hepatobiliary ultrasonography

CALCIUM• important structural constituent of bone and is required for

coagulation, neuromuscular excitability, skeletal muscle contraction, and cardiovascular function.

CALCIUMINDICATIONS• Total Ca concentration is a part of a routine biochemistry profile.• If available, iCa may be a better assessment of Ca balance in animals with hyperproteinemia or

hypoproteinemia, renal disease, acid-base imbalances, or hyperparathyroidism.• Signs suggestive of hypocalcemia, such as facial rubbing, muscle twitching, or tetany or seizures• Animals that are PU/PD, weak, or have a cardiac arrhythmiaCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Cardiovascular• Endocrine and metabolic• Gastrointestinal• Musculoskeletal• Neuromuscular• Renal and urologic• Reproductive

CALCIUMSAMPLECOLLECTION• 1–3 mL of venous bloodHANDLING The sample can be collected into the following:• A plain red-top tube or serum-separator tube (total Ca)• A sodium heparin, or lithium heparin, anticoagulant is also acceptable.• For iCa, samples need to be collected anaerobically, placed on ice, and delivered to the laboratory

immediately or stored in a tightly sealed container to maintain anaerobic conditions. Avoid the use of serum-separator tubes.

• Anticoagulants, which chelate Ca (e.g., EDTA, citrate) or cause precipitation of Ca (e.g., oxalate), are not acceptable.

STORAGE• Total Ca• Refrigerate for short-term storage.• iCa• Heparinized whole blood should be analyzed immediately.• If there is a delay, the sample should be tightly capped to maintain anaerobic conditions and be put on ice.• Serum or plasma stored in an airtight container can be refrigerated or frozen.

CALCIUMSTABILITY• Total Ca• Room temperature: ≈1 week• Refrigerated (2◦–8◦C): ≈3 weeks• Frozen (−20◦C): ≈1 year. However, coprecipitation of Ca with• lipids or fibrin (from plasma) may occur with frozen samples, and• plastic or glass may adsorb Ca during storage.

• iCa• When maintained under anaerobic conditions (i.e., in an airtight• container), iCa concentration in serum or plasma is stable for the• following periods:• Room temperature: ≈3 days• Refrigerated (−4◦C): ≈1 week• Frozen (−20◦C): ≈6 months

PROTOCOL• None

CALCIUMSpecies Normal Range (Total Ca)

Dog 9.0–11.5 mg/dL (2.25–2.88 mmol/L)

Cat 8.0–11.5 mg/dL (2.00–2.88 mmol/L)

CALCIUMSpecies Normal Range (iCa)

Dog 1.15–1.38 mmol/L)

Cat 4.5–5.5 mg/dL (1.13–1.38 mmol/L)

CALCIUMINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Administration of fluorides and oxalate may cause Ca precipitation.• Administration of acetaminophen, cefotaxime, chlorpropamide, or hydralazine can cause

artificial increases in Ca.Drugs That Alter Physiology• Drugs or substances that cause decreases in Ca, including albuterol, anticonvulsants,

asparaginase, aspirin, cisplatin, citrate, mithramycin, diuretics (furosemide), EDTA, fluoride, gastrin, glucagon, glucocorticoids, glucose, insulin, isoniazide, magnesium salts, phenobarbital (long term), phosphate-containing enemas and IV phosphate administration (potassium phosphate), and tetracycline (in pregnancy).

• Drugs or substances that cause increases in Ca include alkaline antacids and antacids with Ca, aluminum hydroxide, anabolic steroids and androgens, Ca salts and parenteral Ca administration, cholecalciferol rodenticides, danazol, dienestrol, diethylstilbestrol, diuretics [chronically administered (chlorthalidone, ergocalciferol, furosemide, thiazides)], estrogen, hydrochlorothiazide, excess oral phosphate binders, propranolol, progesterone, testosterone, theophylline, vitamin A (acute intoxication), and vitamin D.

CALCIUMDisorders That May Alter Results• Total Ca is falsely increased by lipemia and hemolysis (formation of a hemoglobin-

chromogen complex), but iCa is unaffected.• Total Ca is decreased by marked bilirubinemia.Collection Techniques or Handling That May Alter Results• Prolonged occlusion (i.e., 2–3 min) of the vessel during phlebotomy may mildly

increase Ca.• Use of an inappropriate anticoagulant• Carbon dioxide loss because of nonaerobic sample handling can change the iCa

concentration.

CALCIUMInfluence of SignalmentSpecies• NoneBreed• NoneAge• Puppies between 6–24 weeks of age have slightly higher serum Ca

concentrations (1–2 mg/dL) than adults.Gender• NonePregnancy• Small-breed female dogs are at increased risk of hypocalcemia during

the first 3 weeks postpartum, while nursing a litter.

CALCIUMANCILLARY TESTS• A serum chemistry profile (especially albumin, total protein,

phosphorus concentrations)• An imaging technique to look for neoplasia• Blood-gas analysis• PTH and parathyroid hormone–related protein levels as

workup for hypercalcemia of malignancy• Urinary fractional excretion of Ca

CHLORIDE• principal anion in the extracellular fluid compartment.

CHLORIDEINDICATIONS• GI signs• Polyuria and polydipsia• Acid-base derangements• Monitoring of therapy with diuretics, parenteral nutrition, Na or Cl• salt–containing medications or fluidsCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Endocrine and metabolic• Gastrointestinal• Renal and urologic

CHLORIDESAMPLECOLLECTION• 0.5–1.0 mL of venous bloodHANDLING• Collect the sample in a red-top tube or a serum-separator tube.STORAGE• Refrigerate for short-term storage.• Freeze the serum or plasma for long-term storage.STABILITY• Room temperature: 1 day• Refrigerated (2◦–8◦C): 1 week• Frozen (−20◦C): 1 yearPROTOCOL• None

CHLORIDESpecies Normal Range

Dog 107–113 mEq/L

Cat 117–123 mEq/L

CHLORIDEINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Drugs containing halides (e.g., potassium bromide) may cause pseudohyperchloremia.• Halides are measured as Cl by ion-selective electrodes.Drugs That Alter Physiology• Loop and thiazide diuretics and sodium bicarbonate may cause hypochloremia.• Acetazolamide, ammonium chloride, glucocorticoids, and drugs that diminish renal concentrating

ability (e.g., amphotericin) may cause hyperchloremia.Disorders That May Alter Results• In a lipemic sample, pseudohyperchloremia may be diagnosed if a non–ion-selective colorimetric

assay is used, but using a non–ionselective titrimetric method may cause pseudohypochloremia.• Hyperproteinemia may cause pseudohypochloremia if a titrimetric method is used.• Hyperviscosity may alter results if samples are diluted prior to analysis (i.e., by indirect

potentiometry).Collection Techniques or Handling That May Alter Results• None

CHLORIDEInfluence of SignalmentSpecies• NoneBreed• NoneAge• NoneGender• NonePregnancy• None

CHLORIDEHigh Values Low values

PseudohyperchloremiaSample evaporationPotassium bromide therapyLipemia (colorimetric method)

PseudohypochloremiaDilutional artifactLipemia andhyperproteinemia(titrimetric methods)

Normal corrected Cl(concurrent hypernatremia)HemoconcentrationPure water loss (diabetesinsipidus)Hypotonic fluid loss (e.g.,diabetes mellitus)

Normal corrected Cl(concurrent hyponatremia)GI lossThird-space loss (ascites,uroabdomen)Urinary lossRenal failureHypoadrenocorticismKetonuriaEdematous conditionsBurns

Corrected hyperchloremiaExcessive loss of Na (andHCO3) relative to Cl (e.g.,small-bowel diarrhea)Excessive gain of Cl relativeto NaTherapy with Cl-containingsaltsParenteral nutritionFluid therapy with 0.9% NaClor hypertonic salineSalt poisoningRenal retention of ClRenal failure

Corrected hypochloremiaExcessive loss of Cl relativeto NaVomiting Cl-rich stomachcontentsThiazide or loop diureticsHyperadrenocorticismCavitary effusionCongestive heart failureChronic respiratoryacidosisTherapies containing high Naconcentration relativeto ClNa-containing antibioticsSodium bicarbonate

Renal failureRenal tubular acidosisHypoaldosteronismKetoacidotic diabetesmellitusPotassium-sparing diuretics(amiloride, spironolactone)AcetazolamideChronic respiratory alkalosis(decreased renal retentionof HCO3)

CHLORIDEANCILLARY TESTS• Na, potassium, HCO3• Blood-gas analysis, anion gap• Urine fractional excretion of Cl

CHOLESTEROL• type of lipid derived from triglycerides found primarily in

tissues of animal origin

CHOLESTEROLINDICATIONS• Hyperlipidemia• Suspect endocrinopathy• Suspect hepatic disease• Suspect nephrotic syndromeCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• Postvenipuncture bleeding if hepatic coagulation factor synthesis is decreased.CLIENT EDUCATION• The patient must fast for 12 h.BODY SYSTEMS ASSESSED• Endocrine and metabolic• Hepatobiliary• Renal and urologic

CHOLESTEROLSAMPLECOLLECTION• 1 mL of venous bloodHANDLING• A plain red-top, serum-separator tube, or heparin (green-top tube)STORAGE• Refrigerate or freeze the serum for long-term storage.STABILITY• 1 day at room temperature• Refrigerated (2◦–8◦C): 1 week• Frozen: 3 months at −20◦C; several years at −70◦CPROTOCOL• None

CHOLESTEROLSpecies Normal Range

Dog 133–367 mg/dL (3.45–9.50 mmol/L)

Cat 70–229 mg/dL (1.8–5.9 mmol/L)

CHOLESTEROLINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• IV heparin (promotes secretion of lipoprotein lipase and hepatic lipase)• Corticosteroids may cause an increase via multiple mechanisms.Disorders That May Alter Results• Hemolysis and hyperproteinemia artifactually increase reflectance

spectrophotometry results.• Bilirubin and ascorbic acid negatively interfere with enzymatic assays.Collection Techniques or Handling That May Alter Results• Iatrogenic hemolysis• In nonfasted samples, a postprandial cholesterol increase may be mistaken for

metabolic disease.

CHOLESTEROLInfluence of SignalmentSpecies• NoneBreed• NoneAge• Increases with ageGender• NonePregnancy• None

CHOLESTEROLHigh Values Low values

Primary hyperlipidemiaIdiopathic hyperlipidemia ofminiature schnauzersIdiopathichyperchylomicronemiaLipoprotein lipase deficiencyHypercholesterolemia ofbriards

Decreased productionCongenital portosystemic vascular anomaliesHepatic failureMaldigestion/exocrine pancreas insufficiencyMalabsorption/protein-losing enteropathy (especially lymphangiectasia)Severe malnutrition

Increased productionPostprandial hyperlipidemiaProtein-losing nephropathy(nephrotic syndrome)

Other, unknown, or multiplemechanismsHypoadrenocorticism

Decreased lipoprotein clearanceHypothyroidismProtein-losing nephropathy

CHOLESTEROLHigh Values Low values

Other, unknown, or multiplemechanismsDiabetes mellitus (marked)Hyperadrenocorticism (mild)Exogenous corticosteroids(moderate)Acute (necrotizing)pancreatitisObstructive cholestasis (rare)

CHOLESTEROLANCILLARY TESTS• Full chemistry panel for hepatic, renal, and pancreatic

function• Urinalysis to check for proteinuria, glucosuria, and ketonuria• Thyroid function tests• Liver function tests

CREATINE KINASE• cytoplasmic enzyme found within skeletal muscle, cardiac

muscle, smooth muscle, the brain, and nerves. • It is involved in the transfer of phosphate from creatine

phosphate to adenosine triphosphate (ADP) to form ATP.

CREATINE KINASEINDICATIONS• Detection of skeletal muscle injury• Detection of cardiac muscle injuryCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Musculoskeletal• Cardiovascular

CREATINE KINASESAMPLECOLLECTION• 0.5–1.0 mL of venous bloodHANDLING• Serum-separator tube or plain red-top tube• Sodium heparin anticoagulant or lithium heparin anticoagulant is acceptable.STORAGE• Refrigerate or freeze the serum for long-term storage.• Avoid exposing the serum to bright light, which can cause falsely decreased activity.STABILITY• Room temperature: 2 days• Refrigerated (2◦–8◦C): 1 week• Frozen (−15◦ to −25◦C): 1 monthPROTOCOL• None

CREATINE KINASESpecies Normal Range

Dog 48–364 IU/L

Cat 41–448 IU/L

CREATINE KINASEINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Dipyrone administration decreases values.Drugs That Alter Physiology• Corticosteroid administration can increase values.• Insulin administration can activate CK and increase values.• Streptokinase administration can increase CK activity from subsequent reperfusion injury.• Amphotericin B administration can increase values because of muscle damage caused by

severe hypokalemia.• Drugs that can cause immune-mediated polymyositis, increasing CK activity, include

penicillin, D-penicillamine, sulfonamides, and phenytoin.Disorders That May Alter Results• Hemolysis can falsely increase CK.Collection Techniques or Handling That May Alter Results• IM injections administered prior to sampling can increase CK.

CREATINE KINASEInfluence of SignalmentSpecies• Cats have relatively less CK than other species. Therefore, even

small elevations in CK activity are important diagnostically.Breed• NoneAge• Young puppies have a higher CK level than adult dogs.Gender• NonePregnancy• None

CREATINE KINASEHigh Values Low valuesTraumatic muscle injuryPhysical traumaIM injectionPostoperative injury

Not usually clinically significant

Infectious and/or inflammatorymuscle diseaseMasticatory myositis (dogs)Immune-mediated polymyositisHepatozoon sp.Neospora caninumToxoplasma gondiiSarcocystis sp.Miscellaneous muscle diseaseSeizuresSaddle thrombusStrenuous exerciseDirofilariasisBacterial endocarditis

CREATINE KINASEHigh Values Low valuesMetabolic muscle diseaseExertional rhabdomyolysis (racinggreyhounds)Hyperthyroidism (cats)Hypothyroidism (dogs)Malignant hyperthermia (dogs)Anorexia (cats)Inherited/congenital muscle diseaseMusculodystrophyHypokalemic myopathy in Burmese catsMyotonia (dogs)Phosphofructokinase deficiency (dogs)

CREATINE KINASEANCILLARY TESTS• AST determination• 2M antibody test for masticatory muscle myositis• Muscle biopsy• Troponin evaluation

CREATININE• formed by the spontaneous conversion of muscle creatine

into a ring structure.

CREATININEINDICATIONS• Component of the minimum database• To evaluate renal function in clinically ill patients• Diagnosis of uroabdomen• Calculation of GFR and electrolyte fractional excretion rates• In urine, CRT measurement is used to correct other analyte levels for SG variability.CONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Renal and urologic

CREATININESAMPLECOLLECTION• 1–2 mL of venous bloodHANDLING• Plain red-top tube or serum-separator tube• Sodium or lithium heparin anticoagulant (green-top tube) is acceptable.• Centrifuge and remove serum and/or plasma from cellular material within 4 h of collection.STORAGE• Refrigerate or freeze the serum for long-term storage.STABILITY• Serum/Plasma• Room temperature: 1–5 days• Refrigerated (2◦–8◦C): <1 month• Frozen (−18◦C or less): indefinitelyPROTOCOL• None

CREATININESpecies Normal Range

Dog 0.6-2.0 mg/dL

Cat 0.9-2.2 mg/dL

CREATININEINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Lidocaine: increases values (dry chemistries)• Nitrofurantoin: increases values (Jaffe reaction)• Cefoxitin: increases values (Jaffe reaction)• Dobutamine: decreases values• Proline from hyperalimentation fluids: increases valuesDrugs That Alter Physiology• Nephrotoxic drugs such as aminoglycoside antibiotics, amphotericin B, cisplatin,

phenylbutazone, polymyxin B, cephalosporins (occasionally), and sulfamethoxazole (occasionally)

Disorders That May Alter Results• Rhabdomyolysis may increase CRT production slightly.• Cachexia/muscle wasting may decrease CRT concentration.Collection Techniques or Handling That May Alter Results• None

CREATININEInfluence of SignalmentSpecies• NoneBreed• Sighthounds (e.g., greyhounds) have a higher CRT.Age• Kittens that are <2 months of age have higher CRT concentrations than adults.Gender• NonePregnancy• Elevated cardiac output can increase GFR and lower CRT.

LIMITATIONS OF THE TEST• It is a relatively insensitive measure of renal function: CRT does not increase until GFR is

reduced to <25% of normal.• Increased CRT is not specific for renal disease and can be influenced by extrarenal disease.

PrerenalDecreased GFR/renal blood flowHypovolemia: decreased bloodvolume; dehydrationCardiac insufficiencyShockIncreased CRT production(mild increase)Red-meat consumptionIncreased protein catabolism(possible)

Increased GFR/renal blood flowPregnancyHyperthyroidism

RenalAcute and chronic renal failureInflammation/infection:glomerulonephritis, pyelonephritis;tubulointerstitial nephritis,leptospirosis, hemolytic uremicsyndrome

CachexiaNot usually clinically significant

Causes of Abnormal Findings CREATININE

Toxins: ethylene glycol,aminoglycosides, hypercalcemia;myoglobin; phenylbutazone,cisplatin, plants (e.g., Easter lily,grapes, raisins), heavy metalsAmyloidosisHydronephrosisCongenital hypoplasia or aplasia

Not usually clinically significant

PostrenalLower urinary tract obstructionLeakage of urine from the urinarytract: bladder rupture, urethraltrauma, ureteral or renal pelvicobstruction

Causes of Abnormal Findings CREATININE

CREATININEANCILLARY TESTS• Blood/serum urea nitrogen• Urinalysis, including SG• Urinary fractional excretion• Urine protein/creatinine ratio

GLOBULINS• heterogeneous group of >1,000 proteins that perform a variety of different

physiologic functions.• The major site of globulin synthesis is the liver, although the immune system also

contributes significantly

GLOBULINSINDICATIONS• To evaluate unexplained dysproteinemias• To screen for antibody-producing neoplasia (multiple myeloma)• To screen for failure of passive transfer (neonates) or inherited or acquired immune

deficiency (puppies)CONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Hemic, lymphatic, and immune• Hepatobiliary

GLOBULINSSAMPLECOLLECTION• 0.5–2.0 mL of venous bloodHANDLING• Plain red-top tube or serum-separator tube• Sodium heparin or lithium heparin anticoagulant also acceptableSTORAGE• Store at room temperature for short-term use.• Refrigerate for up to 1 month.• Freeze for the long term.STABILITY• Room temperature: 1 week• Refrigerated (2◦–8◦C): 1 month• Frozen (−18◦C): >1 monthPROTOCOL• None

GLOBULINSSpecies Normal Range

Dog 2.7–4.4 g/dL (27–44 g/L)

Cat 2.6–5.1 g/dL (26–51 g/L)

GLOBULINSINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• NoneDisorders That May Alter Results• NoneCollection Techniques or Handling That May Alter Results• None

GLOBULINSInfluence of SignalmentSpecies• NoneBreed• NoneAge• A minimal immunoglobulin level is present at birth. The immunoglobulin concentration rises

rapidly in newborns because of absorption of maternal immunoglobulins after ingestion of colostrum.

• Newborns begin to synthesize immunoglobulins as maternally derived immunoglobulins are metabolized and decline (within 1–5 weeks). Adult levels of immunoglobulins are attained upon reaching young adulthood (6 months to 1 year).

• There is a general increase in globulins with advancing age.Gender• NonePregnancy• The globulin concentration may decrease during the third trimester of pregnancy and

whelping (in association with colostrum production).

GLOBULINSANCILLARY TESTS• Albumin• Total protein• Serum protein electrophoresis to look for monoclonal gammopathy or immunodeficiency• Bence-Jones proteins• Quantification of immunoglobulins through radial immunodiffusion

GLUCOSEINDICATIONS• Weakness• Seizures, altered mentation, or coma• Sepsis• Polyuria-polydipsia• Suspected hepatic or endocrine diseaseCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• Glucose is the first line of tests in diagnosing DM, but additional tests such as fructosamine or

glycosylated hemoglobin may be needed to confirm the diagnosis.• Patients should undergo a fast.BODY SYSTEMS ASSESSED• Endocrine and metabolic• Gastrointestinal• Hepatobiliary• Nervous• Renal and urologic

GLUCOSESAMPLECOLLECTION• 2–3 mL of venous blood• Minimize patient struggling as much as possible.HANDLING• Collect the sample into a plain red-top tube, serum-separator tube, heparin, or EDTA.• To prevent the use of the glucose, separate the serum or plasma from the cellular portion of the

blood soon after sample collection.• A decreased glucose level can be seen within 30 min if serum is not separated from cells with up to a

10% decrease per hour.• The administration of sodium fluoride (NaF) anticoagulant can prevent cellular consumption of

glucose. However, NaF interferes with the glucose oxidase method of glucose determination used in some glucometers.

STORAGE• Refrigeration is recommended.STABILITY• Room temperature: at least 2 days (if the serum or plasma is separated from the cells)• Refrigerated (4◦C): at least 3 days (if the serum or plasma is separated from the cells)• Frozen (−20◦C): at least 1 weekPROTOCOL• None

GLUCOSESpecies Normal Range

Dog 70-120 mg/dL

Cat 70-130 mg/dL

GLUCOSEINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• β-Adrenergic blockers, antihistamines, ethanol, sulfonylureas, salicylates, and anabolic

steroids may decrease blood glucose.• In diabetic patients, recent insulin treatment or the administration of sulfonylurea

compounds such as glipizide may cause hypoglycemia.• Hyperglycemia can be seen with L-asparaginase, β-adrenergic blockers, corticosteroids, α2-

agonist sedatives (e.g., xylazine, detomidine), ketamine, diazoxide, furosemide and thiazide diuretics, acetazolamine, phenothiazines, morphines, megestrol acetate, and heparin.

• Patients receiving parenteral nutrition may also develop hyperglycemia.Disorders That May Alter Results• Hormones such as glucagon, thyroxin, progestins, and estrogens in cats are associated with

hyperglycemia.• The hematocrit will affect assays that use whole blood. An elevated hematocrit will lower

glucose values and vice versa.

GLUCOSECollection Techniques or Handling That May Alter Results• Delay in separation of cells from the serum or plasma may

falsely lower the glucose level. The rate of glucose consumption varies with glucose concentration, temperature, WBC count, and other factors.

• Extreme leukocytosis or bacterial contamination of the sample accelerates glucose consumption.

• Patients, particularly cats, that struggle or are very fearful during sample collection may have transient hyperglycemia due to stimulation of gluconeogenesis from catecholamine secretion.

• Postprandial sampling may elevate glucose concentrations.

GLUCOSEInfluence of SignalmentSpecies• Dogs: DM is usually caused by insulin deficiency as a result of pancreatic β-cell destruction.• Cats: DM is often produced by a combination of defective insulin• secretion and insulin receptor defects.Breed• Hunting breeds of dogs may develop hypoglycemia after time in the field, perhaps due to increased glucose

use.• Glycogen storage diseases are a rare cause of hypoglycemia. Type III glycogen storage disease has been

reported in German shepherds.• Some families of keeshonds have a predilection for DM.Age• Neonates or juvenile animals, particularly toy-breed dogs, can be prone to develop hypoglycemia, perhaps due

to insufficient gluconeogenesis relative to metabolic rate.Gender• Diestrus in bitches has been associated with hyperglycemia as caused by progesterone-stimulated mammary

gland secretion of GH.Pregnancy• Dogs in late pregnancy may develop a ketogenic hypoglycemia, although the causal mechanism has not been

clearly established.

GLUCOSEHigh Values Low values

DM Delayed separation of cells fromserum or plasma

Insulin deficiencyImmune-mediated β-celldestructionPancreatitis

Sepsis

Insulin resistanceHyperadrenocorticismAcromegalyPheochromocytomaGlucagonoma

Paraneoplastic syndrome

Excitement or fear Insulinoma

Hyperthyroidism Leiomyosarcoma

Drug therapy Hepatic insufficiency

GLUCOSEHigh Values Low values

Hepatocutaneous syndrome Hypoadrenocorticism

Exertional—hunting dogs

Juvenile dogs (especiallytoy breeds)Late pregnancy

GLUCOSEANCILLARY TESTSIn Hypoglycemic Patients• CBC and evaluation of WBCs• Analysis of serum bile acids to evaluate hepatic function• Determination of the insulin/glucose ratio in patients suspected of

having an insulinoma• A possible ACTH stimulation test to look for hypoadrenocorticismIn Hyperglycemic Patients• Evaluation of urine glucose, fructosamine, or glycated hemoglobin

to rule out hyperglycemia induced by transient stress or excitement• An ACTH stimulation or low-dose dexamethasone suppression test

to look for hyperadrenocorticism

LACTATE• Lactic acid is the end product of anaerobic glucose

metabolism and is produced daily (e.g., by exercise) but also during pathologic processes (e.g., shock).

LACTATE• INDICATIONS• To assess the presence and severity of tissue hypoperfusion and/or• hypoxia (the higher the lactate level, the worse the problem)• To predict the outcome (the higher the lactate level, the higher the• mortality)• To assess the response to therapy (lactate clearance is correlated with• survival; inability to normalize is correlated with death)• CONTRAINDICATIONS• None• POTENTIAL COMPLICATIONS• None• CLIENT EDUCATION• None• BODY SYSTEMS ASSESSED• Cardiovascular• Endocrine and metabolic• Gastrointestinal• Musculoskeletal

LACTATE• SAMPLE• COLLECTION• 0.5–1.0 mL of blood (peripheral venous, central venous, or arterial).• Use the same source for repeated measurements.• Avoid prolonged restraint and venous stasis during sample collection.• HANDLING• Lithium heparin, sodium fluoride, or indoacetate are the preferred• anticoagulants.• Centrifuge and harvest plasma, which is preferred to whole blood.• Keep the sample on ice or refrigerate it if it is not measured immediately.• STORAGE• Freeze the plasma if measurement is delayed for >30 min (heparin) or• >2 h (fluoride or indoacetate).• STABILITY• Room temperature• 30 min (heparin)• 2 h (indoacetate or fluoride tubes)• Refrigerated (4◦C) or on ice: 2 h• Frozen (−20◦C): stable indefinitely• PROTOCOL• None

LACTATESpecies Normal Range (tMg)

Adult dogs and puppies >70 days of age:

Puppies <4 days of age

4–28 days of age:

1.6 mmol/L

3.8 mmol/L

2.7 mmol/L

Adult cats 1.8 mmol/L

LACTATE• INTERFERING FACTORS• Drugs That May Alter Results or Interpretation• Drugs That Interfere with Test Methodology• None• Drugs That Alter Physiology• Acetaminophen• Activated charcoal• Bicarbonate• Catecholamines• Halothane• Nitroprusside• Propylene glycol• Salicylates• Terbutaline• Disorders That May Alter Results• Seizures or extreme muscular exertion can increase the lactate concentration• (≈4–10 mmol/L), which generally returns to normal in 2 h or• less.• Collection Techniques or Handling That May Alter Results• Stress, trembling, resisting restraint, excitement, venous stasis, and• exercise increase the lactate concentration (≈2.5–5.0 mmol/L), which• generally returns to normal in 2 h or less.• Failure to separate plasma from RBCs falsely increases the result.

LACTATE• Influence of Signalment• Species• Cats have slightly higher normal lactate levels than dogs.• Breed• None• Age• Lactate levels are higher in neonatal puppies <70 days of age.• Gender• None• Pregnancy• None

LACTATEHigh Values Low values

Type A lactic acidosisSystemic hypoperfusion (e.g., shock,heart failure)Regional hypoperfusion (e.g.,gastric/splanchnic ischemia,thromboembolism)Severe hypoxemiaSevere anemiaIncreased anaerobic activity (e.g.,seizures, exercise, trembling)

Sodium citrate anticoagulant

Type B1 lactic acidosisNeoplasiaSepsisRenal failureLiver failure

LACTATEHigh Values Low values

Type B2 lactic acidosisDrugs Toxins (e.g., ethylene glycol,ethanol, sorbitol, xylitol,propylene glycol, carbon monoxide)Type B3 lactic acidosis due to inbornerrors of metabolism (e.g., metabolicmyopathy of Labrador retrievers)

LACTATE• ANCILLARY TESTS• Arterial blood-gas analysis and specific tests (e.g., anion gap,

ethylene• glycol, serum and urine glucose, serum and urine ketones)

may define• the type of acid-base disorder present and its etiology.

MAGNESIUM• second most abundant intracellular cation behind potassium

and is an essential cofactor in hundreds of enzymatic reactions, as well as being associated with ATP production, ion transport, and establishment of transmembrane electrical gradients

MAGNESIUMINDICATIONS• Component of a routine biochemical profile (tMg)• Monitoring in critically ill patients (tMg and iMg)CONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• Serum total Mg levels may be normal despite an underlying deficiency.BODY SYSTEMS ASSESSED• Cardiovascular• Endocrine and metabolic• Gastrointestinal• Neuromuscular• Renal and urologic

MAGNESIUMSAMPLECOLLECTION• 1–3 mL of venous bloodHANDLING• tMg: Collect samples into plain red-top tube, serum-separator tube, or heparin

anticoagulant. Anticoagulants that chelate Mg (e.g., EDTA, citrate) are not acceptable.

• iMg: Collect samples anaerobically into heparin or a plain redtop tube, place them on ice, and analyze them immediately or store separated serum or plasma in a tightly sealed container to maintain anaerobic conditions.

STORAGE• tMg: Refrigerate samples for short-term storage. Freeze serum or plasma for

long-term storage.• iMg: If necessary, serum or plasma can be refrigerated or frozen in an airtight

container.

MAGNESIUMSTABILITY tMg• Room temperature: 1 week• Refrigerated (2◦–8◦C): 1 week• Frozen (−20◦C): ≈1 year iMg• Room temperature: 1 day• Refrigerated (2◦–8◦C): 3 days• Frozen (−20◦C): 1 month

MAGNESIUMSpecies Normal Range (tMg)

Dog 107–113 mEq/L

Cat 1.7–2.6 mg/dL (0.70–1.07 mmol/L)

MAGNESIUMSpecies Normal Range (iMg)

Dog 0.92–1.26 mg/dL (0.38–0.52 mmol/L)

Cat 1.14–1.53 mg/dL (0.47–0.63 mmol/L)

MAGNESIUMINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Artifactual decreases caused by citrates, Ca gluconate, glucuronic acid, and cefotaxime (if tobramycin is

present)• Artifactual increases caused by cefotaxime, trichloroacetic acid, and CaDrugs That Alter Physiology• Physiologic increases

– Caused by prolonged aspirin therapy, lithium, Mg salts, medroxyprogesterone, and progesterone

• Physiologic decreases– Nephrotoxicity: aminoglycosides, amphotericin B, cisplatin, cyclosporine,

• ticarcillin• Citrates may chelate Mg (blood transfusions).• Decreased intestinal absorption: neomycin, Ca salts, laxatives• Enhanced renal loss: digoxin, furosemide, thiazides, mannitol, saline diuresis• Intracellular shifts with the administration of insulin, glucose, or amino acidsDisorders That May Alter Results• tMg falsely increased by in vivo hemolysis, hypercalcemia, or hyperproteinemia• tMg falsely decreased by hyperbilirubinemia, lipemia, or hypoproteinemia• Acid-base disorders may result in shifts between iMg and proteinbound• Mg similar to those observed with Ca.

MAGNESIUMCollection Techniques or Handling That May Alter Results• Mg falsely decreased by the use of inappropriate

anticoagulants such as citrate, EDTA, lithium heparin, sodium fluoride, or oxalates or by the use of siliconized blood tubes

• Elevated by in vitro hemolysis with Mg release from erythrocytes

• iMg decreased by increased pH from delayed sample processing or exposure to air

MAGNESIUMInfluence of SignalmentSpecies• NoneBreed• NoneAge• NoneGender• NonePregnancy• Maternal Mg may affect the fetus

MAGNESIUMANCILLARY TESTS• Chemistry profile including Ca and electrolytes• Urinary Mg levels to look for renal loss

PHOSPHORUS• Chief component of hydroxyapatite in bone and cellular

membranes, found intracellularly and extracellularly, and is present in organic and inorganic forms

PHOSPHORUSINDICATIONS• Part of a routine biochemistry profileAnimals with severe hypophosphatemia may exhibit the following:• Pallor and/or hemoglobinuria secondary to hemolytic anemia• Muscle weakness or pain associated with rhabdomyolysis• Depression; neurologic signs• Tachypnea, dyspenia, or shallow, rapid breathing because of hypoxia and/or

compromised respiratory muscle function• Anorexia, vomiting, and nausea associated with intestinal ileus• Animals with hyperphosphatemia may show signs of renal failure with or without

uremia (e.g., polyuria-polydipsia, weight loss, anorexia, lethargy, vomiting, oral ulceration).

• Nonazotemic animals with hyperphosphatemia may show polyphagia, restlessness, and weight loss. If hyperphosphatemia is acute, the resulting hypocalcemia may cause tetany and/or animals may exhibit vascular collapse, or present with vomiting, bloody diarrhea, ataxia, and depression.

PHOSPHORUSCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Endocrine and metabolic• Hemic, lymphatic, and immune• Gastrointestinal• Musculoskeletal• Neuromuscular• Renal and urologic

PHOSPHORUSSAMPLECOLLECTION• 1–2 mL of venous bloodHANDLING• Collect the sample into red-top tube, serum-separator tube, or heparin (green top).• Separate the serum (or plasma) from cells within 1 h of sample collection to avoid in vitro

hemolysis.STORAGE• Separation from cells is recommended before the sample is stored.• For short-term storage, refrigeration is recommended.• For long-term storage, freezing is recommended.STABILITY• Refrigerated (2◦–8◦C): ≈1 week• Frozen (−20◦C): ≈6 monthsPROTOCOL• None

PHOSPHORUSSpecies Normal Range

Dog 2.9–5.3 mg/dL (0.94–1.71 mmol/L)

Cat 3.0–6.1 mg/dL (0.97–1.97 mmol/L)

PHOSPHORUSINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• Drugs or substances that potentially cause artifactual decreases in serum phosphorus include

phenothiazines, cefotaxime, citrates, mannitol, oxalate, and tartrates (which may decrease or inhibit color development of the indicator); and promethazine.

• Drugs or substances that potentially cause artifactual increases in serum phosphorus include aminosalicylic acid, bilirubin, detergents contaminating glassware, fat emulsions, hemoglobin, lipemia, methotrexate, naproxen, and rifampin.

Drugs That Alter Physiology• Drugs that potentially cause decreases in serum phosphorus concentrations include acetazolamide,

albuterol, aluminum-containing antacids, amino acids, anesthetic agents, anticonvulsants, corticosteroids, epinephrine, estrogens, fructose, glucose, hydrochlorothiazide (occasionally with prolonged treatment), insulin, isoniazid, magnesium hydroxide, and sucralfate.

• Drugs that potentially cause increases in serum phosphorus concentrations include alanine, aluminum hydroxide, anabolic steroids, androgens, β-adrenergic blockers, ergocalciferol, furosemide, growth hormone, hydrochlorothiazide, medroxyprogesterone, minocycline, phosphates, vitamin D, and xylitol.

• Nephrotoxic drugs (e.g., aminoglycoside antibiotics, amphotericin B, tetracycline) that decrease GFR can also elevate phosphorus concentration.

PHOSPHORUSDisorders That May Alter Results• Hemolysis can potentially cause false increases in the phosphorus concentration

because of the release of phosphates and phospholipids from erythrocytes.• Depending on the assay methodology or the system, lipemia or hyperproteinemia

may result in false increases. Hyperbilirubinemia may interfere with the assay, causing either false increases or decreases.

• Thrombocytosis and monoclonal gammopathies have been reported to cause false increases.

• In some dogs with immune-mediated hemolytic, anemia phosphorus may be spuriously low.

Collection Techniques or Handling That May Alter Results• Poor sample collection technique may result in hemolysis• Failure to separate cells from serum or plasma within a short period may result in

falsely increased phosphorus concentrations because intracellular phosphorus may leak from aging blood cells.

PHOSPHORUSInfluence of SignalmentSpecies• NoneBreed• NoneAge• Young, growing dogs (up to ≈1 year of age) have higher serum phosphorus

concentrations than adults (4–9 mg/dL) because of bone remodeling during growth.• The effect of age is less pronounced in cats, although young cats tend to have

slightly higher serum phosphorus concentrations than adults.Gender• NonePregnancy• None

PHOSPHORUSANCILLARY TESTS• CBC (especially PCV)• Serum chemistry profile (especially BUN, creatinine, and

calcium)• Urinalysis (especially urine specific gravity)

POTASSIUM• principal cation of the intracellular fluid (ICF) compartment

POTASSIUMINDICATIONS• GI signs (e.g., vomiting, diarrhea, painful abdomen)• Cardiac arrhythmias• Skeletal muscle weakness or hyperexcitability• Polyuria-polydipsia• Renal disease• Urethral blockage or uroabdomen• Diabetic ketoacidosis (DKA)• Monitoring therapy with insulin, angiotensin-converting enzyme (ACE) inhibitors, K-sparing diuretics, K

supplementation (IV or oral), K penicillin G, or heparinCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Cardiovascular• Endocrine and metabolic• Gastrointestinal• Renal and urologic

POTASSIUMSAMPLE• COLLECTION• 0.5–1.0 mL of venous bloodHANDLING• Collect the sample into a red-top tube or serum-separator tube.STORAGE• Refrigeration is recommended for short-term storage.• Freeze the serum or plasma for long-term storage.STABILITY• Room temperature: 1 day• Refrigerated (2◦–8◦C): 1 week• Frozen (−20◦C): 1 yearPROTOCOL• None

POTASSIUMSpecies Normal Range

Dog 3.5–5.5 mEq/L

Cat 3.5–5.5 mEq/L

POTASSIUMINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• Hypokalemia can be caused by loop and thiazide diuretics, acetazolamide,

mineralocorticoids, insulin, glucose-containing fluids, K-free fluids, Na bicarbonate, amphotericin B, ammonium chloride, and K-free dialysate.

• Hyperkalemia can be caused by K chloride (IV or oral), digitalis overdose, trimethoprim, ACE inhibitors, K-sparing diuretics, nonspecific β blockers, and nephrotoxic NSAIDs.

Disorders That May Alter Results• Thrombocytosis and leukocytosis may cause hyperkalemia (leak of K from cells).• Hemolysis in dogs and cats with phosphofructokinase deficiency may cause

hyperkalemia.• Severe bilirubinemia may cause slightly increased levels of serum K if measured with

ion-selective electrodes.• Metabolic acidosis may cause hyperkalemia due to a normal physiologic response.

POTASSIUMCollection Techniques or Handling That May Alter Results• A poor venipuncture technique that causes hemolysis may

increase levels of K in some dog breeds.• K oxalate or EDTA anticoagulants cause an artificially high

measured K value.• Plasma K levels are higher than serum K levels.

POTASSIUMInfluence of SignalmentSpecies• NoneBreed• In vitro hemolysis of K-rich erythrocytes in the Akita and Shiba Inu breeds may cause

pseudohyperkalemia (the use of lithium heparin collection tubes is recommended).• In vivo hemolysis in phosphofructokinase deficiency in predisposed canine breeds (i.e.,

English springer spaniels, American cocker spaniels) may elevate serum K levels.Age• In vitro hemolysis of K-rich erythrocytes in some neonates may cause

pseudohyperkalemia.Gender• See the Pregnancy section.Pregnancy• Concurrent hyperkalemia and hyponatremia may occur in sick lateterm pregnant dogs.

POTASSIUMANCILLARY TESTS• Evaluation of Na, chloride, and magnesium levels to look for concurrent

electrolyte derangements• Blood-gas evaluation, anion gap to look for acid-base abnormalities• An ACTH stimulation test to rule out hypoadrenocorticism• Urinalysis to look for proteinuria, hematuria, pyuria, glucosuria, and• ketonuria• Determination of the urinary fractional excretion of K to rule out• RTA• Fecal flotation to rule out GI parasitism• Electrocardiography to look for hyperkalemic arrhythmias• Thoracic and abdominal radiography and ultrasonography to rule out cavitary

effusion and look for enlargement or abnormal architecture of abdominal organs and evidence of an intact bladder

SODIUM• principal cation in the extracellular fluid (ECF) compartment.• Na is primarily absorbed in the small intestine.

SODIUMINDICATIONS• Cavitary effusion• Dehydration• Edema• GI signs (e.g., vomiting, diarrhea, weight loss, inappetence)• Monitoring of diuretic therapy• Monitoring of treatment for hypoadrenocorticism• Muscle weakness• Neurologic abnormalities (e.g., changes in mentation or behavior, seizures)• Polyuria-polydipsia• Renal diseaseCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Endocrine and metabolic• Gastrointestinal• Hepatobiliary• Renal and urologic

SODIUMSAMPLE• COLLECTION• 0.5–1.0 mL of venous bloodHANDLING• Collect the sample into red-top tube, serum-separator tube, or lithium heparin.STORAGE• Refrigeration is recommended for short-term storage.• Freeze the serum or plasma for long-term storage.• Store in an airtight container to avoid evaporation.STABILITY• Room temperature: 1 day• Refrigerated (2◦–8◦C): 1 week• Frozen (−20◦C): 1 yearPROTOCOL• None

SODIUMSpecies Normal Range

Dog 140–150 mEq/L

Cat 150–160 mEq/L

SODIUMINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• Synthetic adrenocortical steroids (e.g., fludrocortisone,

desoxycorticosterone acetate/pivalate), corticosteroids, lactulose, Na bicarbonate, Na phosphate enemas, hypertonic saline fluids, and amphotericin may cause hypernatremia.

• Loop and thiazide diuretics, K-sparing diuretics (i.e., spironolactone, triamterene), angiotensin-converting enzyme (ACE) inhibitors, Nadeficient fluids, trimethoprim combined with diuretics, NSAIDs, and sulfonylureas may cause hyponatremia.

• Mannitol therapy (hyperosmolar) may cause pseudohyponatremia.

SODIUMDisorders That May Alter Results• Dehydration may cause pseudohypernatremia.• Hyperosmolar states (hyperglycemia) may cause

pseudohyponatremia.• Hyperproteinemia, hyperviscosity, and

hyperlipemia/lipidemia may cause pseudohyponatremia.Collection Techniques or Handling That May Alter Results• Samples collected via IV catheters may cause spurious Na

readings, depending on the fluid being administered.• Samples combined with Na-containing anticoagulants may

cause pseudohypernatremia.

SODIUMInfluence of SignalmentSpecies• NoneBreed• NoneAge• NoneGender• See the Pregnancy section.Pregnancy• Hyperkalemia and hyponatremia may be seen in ill, pregnant dogs.

SODIUMANCILLARY TESTS• Evaluation of K and chloride concentrations to rule out

concurrent electrolyte derangements• Evaluation of blood gas, anion gap, and osmolality• An ACTH stimulation test to rule out hypoadrenocorticism• Fecal flotation to rule out GI parasitism (especially trichuriasis)• Urinary fractional excretion of Na to rule out renal tubular

acidosis• A water-deprivation test (modified) to rule out diabetes

insipidus• Fluid analysis of any effusion

UREA NITROGENINDICATIONS• Screen for renal function• Marker of liver function/insufficiencyCONTRAINDICATIONS• NonePOTENTIAL COMPLICATIONS• NoneCLIENT EDUCATION• NoneBODY SYSTEMS ASSESSED• Hepatobiliary• Renal and urologic

UREA NITROGENSAMPLECOLLECTION• 0.5–2.0 mL of venous bloodHANDLING• Use a plain red-top tube or serum-separator tube.• The use of EDTA, sodium heparin, or lithium heparin anticoagulant is

acceptable.STORAGE• Refrigerate or freeze the separated serum or plasma for long-term storage.STABILITY• Room temperature: 1 day• Refrigerated (2◦–8◦C): 1 weekPROTOCOL• None

BLOOD UREA NITROGENSpecies Normal Range

Dog 8-29 mg/dL

Cat 15-33 mg/dL

UREA NITROGENINTERFERING FACTORSDrugs That May Alter Results or InterpretationDrugs That Interfere with Test Methodology• NoneDrugs That Alter Physiology• Increased (mildly) by drugs that increase protein catabolism (e.g., tetracycline)• Decreased by drugs that decrease protein catabolism (e.g., anabolic steroids)• Decreased by drugs that promote polyuria-polydipsia (e.g., glucocorticoids)• Increased by nephrotoxic drugs, including amphotericin B, aminoglycoside antibiotics (e.g.,

amikacin, gentamicin, kanamycin, tobramycin), and high NSAID doses (e.g., aspirin, carprofen, phenylbutazone, ketoprofen)

Disorders That May Alter Results• Hemolysis can increase BUN results obtained by reflectance spectrophotometry through

interference with light transmission.Collection Techniques or Handling That May Alter Results• Contamination of the sample with quaternary ammonium disinfectants (e.g., benzalkonium

chloride) can increase BUN results obtained by reflectance spectrophotometry.

UREA NITROGENInfluence of SignalmentSpecies• NoneBreed• NoneAge• Neonatal puppies ≤1 month of age have slightly increased urea levels;

embryonic kidney development is not complete until at least week 3 of life.• Puppies that are 2–3 months old have slightly decreased urea levels because

of rapid growth and increased anabolic state.Gender• NonePregnancy• None

UREA NITROGENLIMITATIONS OF THE TEST• The glomerular filtration rate must be reduced to ≤25% of normal

before BUN levels rise above normal.• Overhydration or dehydration can affect levels by altering tubular

reabsorption.Sensitivity, Specificity, and Positive and Negative Predictive Values• Ability of Azostix to identify abnormal BUN concentrations:• Sensitivity: 86.4%• Specificity: 90.3%• Negative predictive value: 96.5%• Positive predictive value: 65.5%. Test strips tend to underestimate• BUN levels, missing a significant number of patients with elevated BUN.

UREA NITROGENHigh Values Low values

PrerenalDehydration, hypovolemia, or shockBlood lossBurnsDecreased cardiac outputSepsis

Hepatic insufficiency

RenalCauses of chronic renal failureAcute tubular necrosis due toischemia, nephrotoxins, severeintravascular hemolysis, ormyoglobinuriaGlomerulonephritisPyelonephritis (e.g., leptospirosis)

Nonrenal causes of polyuria-polydipsia

PostrenalUrinary tract obstructionUrinary tract rupture

Significant protein loss intourine or GI tractAscitesLow-protein diet or starvationOverhydration

UREA NITROGENHigh Values Low values

GI hemorrhage Hepatic insufficiency

High-protein dietNonrenal causes of polyuria-polydipsia

Increased protein catabolism due tofever or marked tissue necrosis

Significant protein loss into urine or GI tract

Ascites

Low-protein diet or starvation

Overhydration

UREA NITROGENANCILLARY TESTS• Urinalysis• Ultrasonography to identify abdominal fluid in an animal with

a ruptured bladder• Fecal occult blood test• Evaluation of serum or urine bile acid levels to assess liver

function

Reference:• Blackwell’s Five-Minute Veterinary Consult: Laboratory Tests

and Diagnostic Procedures: Canine & Feline (www.wiley.com/wiley-Blackwell)

Blood chemistry (Dogs and Cats)

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