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Dr. Doaa A. Ghareeb, Ph.D.
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Normal Values Adults (Wintergreen method): Men under 50 yearsold:lessthan 15 mm/hr. (7 and 17)
Men over 50 yearsold:lessthan 20 mm/hr.
Women under 50 yearsold:lessthan 20 mm/hr.
Women over 50 yearsold:lessthan 30 mm/hr.
Children (Westergren method): Newborn: 0 to 2 mm/hr.
Neonatalto puberty: 3 to 13 mm/hr.
It isonly usefulfor diagnosing threediseases:myeloma, temporalarteritis and polymyalgiarheumatica (in which it may exceed 100mm/hour).
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C-reactive protein (CRP) isa plasma protein.
CRP isa member ofthe classofacute phase
protein producedby theliver as itslevels
risedramatically during inflammatoryprocessesoccurring in thebody.
It isthoughttoassist in complementbinding
toforeign anddamaged cellsandenhances
phagocytosis. CRP isused mainly asa marker of
inflammation.
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Coagulation isa complex processby whichblood
formssolid clots.
isordersof coagulation can leadtoan increased
risk ofbleeding and/or clotting. Coagulation involvesbotha cellular (platelet)
anda protein (coagulation factor) component.
Coagulation time Thetime requiredfor bloodto
coagulate in a glasstube prolonged in haemophiliaand in the presenceof
obstructive jaundice, someanaemiasand
leukaemias, andsomeofthe infectiousdiseases.
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Bleeding time isa medicaltestdoneon someonetoassesstheir plateletfunction.
iseasesthat cause prolongedbleeding time includethrombocytopeniaanddisseminated intravascularcoagulation ( IC).
Aspirin andother cyclooxygenase inhibitors can prolongbleeding timesignificantly.
Whilewarfarin andheparin havetheir major effectson
coagulation factors, an increasedbleeding time issometimesseen withuseofthese medicationsaswell. Normalvaluesfallbetween 2 - 9 minutesdepending on
the methodused.Alancetor scalpelblade isusedto makeastabwoundon
theundersideoftheforearm.
Thetimefrom when thestabwound is madeuntilallbleeding hasstopped is measuredand is calledthebleeding time.
Every 30 seconds, filter paper or a paper towel isusedtodrawofftheblood.
Thetest isfinishedwhen bleeding hasstopped completely.
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It is measuredasthetimefor clotformationafter exogenousthrombin isaddedto citratedplasma.
Uses:
Therapeutic leveloftheanticoagulant Heparin.
etecting the presenceofafibrinogen abnormality
Procedure:
1 part blood + 9 part citrate or oxalate
centrifugation plasmaPlasma + thrombin reagent clot
formation time
TTor TCT isthetimebetween theaddition ofthethrombin andthe clotformation is recorded
asthethrombin clotting time
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Referencevalue:
Lessthan 21 seconds.
Abnormalvalue:
heparin therapy
Hypofibrinogenemia
fibrinogen abnormality
Lupusanticoagulant
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The prothrombin time isthetime ittakesplasmato clotafter addition oftissuefactor.
Or the rateatwhich prothrombin isconvertedtothrombin in citratedbloodwithadded calcium
measuresofthequality extrinsic pathwayofcoagulation.
PT measuresfactorsII, V, VII, X andfibrinogen
The prothrombin ratio The prothrombin ratio isthe prothrombin timefor a
patient, dividedby the resultfor control plasma.
reference range:12-15 seconds
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Lowlevelsofblood proteins (blood clottingfactors).
ecrease in activity ofany ofthefactors.
T
heabsenceofany ofthefactors Deficiencies in vitamin K, which can be caused
by warfarin, malabsorption or lack of intestinalcolonization by bacteria (suchas in newborns).
The presenceofasubstancethatblocksthe
activity ofany ofthefactors An abnormal prothrombin time isoften caused
by liver diseaseor injury or by treatmentwiththe medication warfarin, which isusedtopreventtheformation ofblood clots.
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Medicationsthat can affecttheaction ofblood-thinners (suchaswarfarin)andvitamin K, which in turn affectsthePT result,including antibiotics, aspirin, cimetidine (Tagamet),barbiturates, birth control pills, hormone replacementtherapy(HRT), andvitamin K supplements
Severediarrheaor vomiting that causesfluidlossanddehydration, which may increase prothrombin time.
Ifdiarrhea is causedby poor absorption of nutrients, vitamins,and mineralsfrom the intestinaltract (malabsorptionsyndrome), PT may increasebecauseofavitamin K deficiency
Foodsthat contain vitamin K, suchasbeefliver, pork liver,
green tea, broccoli, andsoybean products Excessiveuseofalcohol
Laxatives
Someherbal productsor natural remedies
Somelaboratoriesusea mechanical measurement, whicheliminates interferencesfrom lipemic and icteric samples.
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or activated partialthromboplastin time
(aPTTor APTT) isa performance indicator
measuring theefficacy ofboththe "intrinsic"
andthe common coagulation pathways.Normal values and interpretation
Normalvalues may vary from labtolab.
Partial thromboplastin time (PTT): 3045 seconds
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Deficiency or abnormality ofoneofthebloodclotting factorsor another substance neededtoclotblood. Adeficiency ofoneor moreofthesefactors results in ableeding disorder (suchashemophilia).
liver disease, kidney disease, or treatmentwithmedicationssuchasheparin or warfarin(Coumadin)thatareusedto preventtheformation ofblood clots.
Antiphospholipid antibody syndromeandlupusanticoagulantsyndromethat can causeabnormalclotting or blood clotformation.
Useofaspirin during heparin therapy, sothePTTvalue needstobe closely monitored
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