How to evaluate anemia using MCV, RDW and RETIC count

How to assess different RBC shapes reported in the PBS

How to deal with leukocyte abnormalities seen on PBS

The causes of thrombocytosis and thrombocytopenia

Role of MCV ◦ mean corpuscular volume

Formula (2-10 yrs old)◦ Lower limit: 70 fL + age in years

◦ Upper limit: 84 fL + ( age in yrs x 0.6 ), until upper limit of 96 is reached

MCH (Mean Corpuscular Hb) MCHC (Mean Corpuscular Hb conc)

- normo/hyper/hypo chromic- Used in

- iron deficiency - - Spherocytosis -

7 year old

LL: 77 fL

UL: 88.2 fL

-Expressed as % of circulating rbc’s

-Take up reticulin stain (supravital):

bec of inc RNA

-N = 0.5 % to 1.5 %

or = .005 to .015

Provide crucial info on RATE of red cell production

2 broad classes of anemias1. 2 red cell loss or destruction – inc retic

- e.g. hemolysis, blood loss2. Dec red cell production – dec retic

e.g. aplastic, iron deficiency

Anemic patient --> increased retic

so have to correct: retic observed x px Hct / 0.45

Example:Hb 50 Hct 0.15Retic count=.045=

4.5 %

Corrected retic =4.5% x .15/.45 = 1.5

%( N = 0.5-1.5%)

More accurate Compute as ff: RBC (in n x 1012 )

x # retic/1000 rbc x 1000Normal = 40,000 – 100,000/uL

Compute for absolute retic count :Hb 90RBC 3 x 1012 /L Retic .015

45,000 retics / uL

Increased MCV◦ High retic◦ Low retic

Decreased MCV◦ High retic◦ Low retic

Normal MCV◦ High retic◦ Low retic

Increased Retic◦Acute blood loss◦Hemolysis

> Increased MCV- cased by inc # retics retics have a large cellular volume

Increased MCV◦ High retic◦ Low retic

Decreased MCV◦ High retic◦ Low retic

Normal MCV◦ High retic◦ Low retic

1. Bone Marrow Failure• Retic count greatly dec for degree of anemia-----------------------------------------------------------------E.g. Known case of Aplastic anemia RBC 1.73 Hb 52 Hct 0.15 Retic = 1 % or 0.010> Compute for corrected retic count % absolute

retic

2. Megaloblastic disorders Folate and Vit B 12 deficiency Other things seen :

Hypersegmentation of PMN’s Macroovalocytosis Megaloblastic changes in BM

3. Alcohol direct toxic effect on BM

4. Anti-metabolitesa. Methotrexate (folic acid anti-metabolite)b. Co-trimoxazole

5. Hypothyroidisma. Causes red cell hypoplasiab. Usually normocytic/normochromicc. Macrocytosis may develop

Caused by insufficient Hb synthesis

Mostly caused by:◦ Iron deficiency◦ Inability to use iron

Chronic disease Thalassemia Lead poisoning Sideroblastic anemia

Increased retic◦ Thalassemia

Normal /decreased retic◦ Fe deficiency◦ Anemia of Chronic

Disease◦ Thalassemia trait◦ Sideroblastic anemia

hardest differentials !

Common cause in 1-3 years of age

As iron stores become depleted:◦RDW serum Fe

MCV anemia

First manifestation : RDW

Reasonable approach: Oral iron replacement

(+) response: Hb by 15-20 in 1 month

PRESUMPTIVE DX MADE !

Quantitative measure of anisocytosis The greater the # of sizes of rbc’s, the

higher the RDW Normal = 11.5-14.5 No subnormal values have been reported

HIGH ( FGHI- C )◦ Iron deficiency◦ Hb H disease◦ Fragmentation◦ G-6PD◦ Chronic disease

Increased retic◦ Thalassemia

Normal /decreased retic◦ Fe deficiency◦Anemia of

Chronic Disease◦ Thalassemia trait◦ Sideroblastic anemia

hardest differentials !

Mild to moderate anemia (Hb 100 – 110) Slight inc RDW; dec Fe, inc Ferritin Px has chronic INFLAMMATION Disturbs iron recycling iron left trapped in

RES◦ Cytokines IL-1, IL-6 inc ferritin syn empty

ferritin shells provide excess iron storage capacity iron sequestered in RES

MCV NORMAL

INC RETIC DEC RETIC N OR DEC RETIC

1. HEMOLYSIS2. BLOOD LOSS

MCV NORMAL

INC RETIC DEC RETIC N OR DEC RETIC

1. BALANCED2. PRCA/TEC3. APLASTIC4. HYPOTHYROIDISM5. REPLACEMENT OF MARROW

MCV NORMAL

INC RETIC DEC RETIC N OR DEC RETIC

1. CHRONIC INFECTION2. RENAL DISEASE3. HYPERPARATHYROID4. LIVER DISEASE

Cause:◦ erythropoeitin

insufficiency◦ Serum inhibitors of

erythropoeisis accumulate in uremic patients

◦ Acanthocytosis◦ Shortened rbc life

span

When BUN > 150 mg/dL

Cytoplasmic fragments ; no nucleus Life span = 7-10 days 1/3 in spleen, 2/3 in circulation Size= 1 – 4 um

◦ Large Young 2 peripheral destruction

◦ Small or normal Production defect

Platelet count > 600,000 Rarely causes complications !

◦ Therefore, antiplatelet tx is rarely indicated◦ Kawasaki is an exception

Hemolytic anemia Hemorrhage Infection Iron def anemia Vit E deficiency Vascular Collagen

disorders

Post-splenectomy Post-op Inflammatory Bowel

Dis Trauma Tumors Syndrome, kawasaki Syndrome,

nephrotic Syndrome,

myeloprolifHIV is the PITS !

Immune Platelet Destruction Infections Platelet clumping

- falsely low - 2 inadequate coagulation

Anisocytosis◦ Microcytes◦ Macrocytes◦ Normocytes

Poikilocytosis◦ Different shapes

Severe hemolysis◦ Nucleated rbc’s◦ Schistocytes: helmet cells, triangle cells, bite cells◦ Spherocytes (immune mediated)◦ acanthocytes

Target cells◦ Liver disease◦ Thalassemia◦ Iron deficiency◦ Post-splenectomy

Elliptocyte◦ Elliptocytosis◦ Megaloblastic

anemia◦ Myelofibrosis◦ Thalassemia

Normochrom ovalocyte◦ Ovalocytosis◦ Thalassemia

Hypochrom ovalocyte◦ Iron deficiency

Macrocytic ovalocyte◦ Megaloblastic

anemia

Blister cell◦ Microangiopathic

hemolytic anemia Tailed RBC

◦ Megaloblastic anemias

◦ Iron deficiency Tear drop

◦ Hypersplenism◦ Thalassemia◦ Hemolytic Anemia

Schistocytes◦ hemolytic anemia◦ Hypersplenism◦ Megaloblastic

anemia◦ Thalassemia◦ Acute Leukemia◦ Post severe burns

10 year old with Hb 80, WBC 9 plt 350. On co-tri for repeated UTI. MCV 102 MCH 340 Retic ct 0.002

What is most likely diagnosis ?a. Fe deficiencyb. Megaloblastic anemiac. Diamond Blackfan Anemiad. Hemolytic anemia

B

MEGALOBLASTICANEMIA

(Prob 2 folate def)

The ff is a cause of thrombocytosisA. Immune thrombocytopenic purpura

B. Pregnancy C. Iron deficiency anemia D. Renal failure

C

Iron deficiency anemia

Compute absolute retic countHb 45RBC 1.5 x 1012 / LRetic count: 0.016

24,000 / uL

Which presents as a microcytic anemiaA. B-thalassemiaB. Hemolytic AnemiaC. Aplastic AnemiaD. Anemia 2 blood loss

A

B- Thalassemia