4 Th Hematology Lecture

8/8/2019 4 Th Hematology Lecture

1/13

Dr. Doaa A. Ghareeb, Ph.D.


2/13

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).


3/13

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.


4/13

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.


5/13

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.


6/13

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


7/13

Referencevalue:

Lessthan 21 seconds.

Abnormalvalue:

heparin therapy

Hypofibrinogenemia

fibrinogen abnormality

Lupusanticoagulant


8/13

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


9/13

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.


10/13

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.


11/13

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


12/13

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


13/13

Thank You For YourThank You For Your

AttentionAttention

Documents

4 Th Hematology Lecture