The document discusses prothrombin time (PT) and activated partial thromboplastin time (APTT) tests. PT measures the extrinsic and common coagulation pathway, while APTT measures the intrinsic and common pathways. Both tests are used to detect bleeding disorders and monitor anticoagulant therapy. The document describes the principles, materials, procedures, normal values and causes of abnormal PT and APTT results. Prolonged PT can indicate liver disease or a fibrinogen abnormality. Prolonged APTT suggests a coagulation factor deficiency and can be seen in lupus or disseminated intravascular coagulation.

1. 10/28/2021
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TIME
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2. PROTHROMBIN TIME
• THIS TEST IS OFTEN KNOWN AS THE “QUICK”
TIME AFTER Dr. A. QUICK ,WHO DESCRIBED IT
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3. DEFINITION
TIME REQUIRED FOR CLOTTING OF CITRATE OR OXALATE
PLASMA IN A GLASS TUBE AFTER THE ADDITION OF CALCIUM
AND TISSUE THROMBOPLASTIN
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4. MATERIALS REQUIREDD
• WATER BATH
• STOP WATCH
• TEST TUBES
• BRAIN THROMBOPLASTIN (COMMERCIAL NAME
THROMBOKINASES TABLETS )
• 0.156g/dl CALCIUM CHLORIDE
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5. PRINCIPLE
• THROMBIN KINASE (THROMBOPLASTIN PREPARATION OF
HUMAN /RABBIT BRAIN )CONTAINING CALCIUM IONS IS
ADDED TO CITRATED PLASMA
• COAGULATION MECHANISM IS TRIGGERED AND THE
CLOTTING TIME IS RECORDED AFTER THE ADDITION OF
THROMBOKINASE IN ADDITION TO CALCIUM IONS
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6. PROCEDURE
• KEEP 2ml OF CALCIUM CHLORIDE AT 37 c IN A TEST TUBE
• PIPETTE 0.1 ml OF PLASMA IN A SMALL TEST TUBE
• ADD 0.1ml OF BRAIN THROMBOPLASTIN AND MIX
• WAIT FOR 2 MINUTES
• ADD 0.1ml OF PRE-WARMED CALCIUM CHLORIDE,MIX AND
START THE STOP WATCH
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7. PROCEDURE
• HOLD THE TUBE IN FRONT OF SOURCE OF LIGHT
• KEEP TITLING THE TUBE GENTLY
• AT THE APPEARANCE OF FIBRIN CLOT,STOP THE WATCH
IMMEDIATELY
• RECORD THE TIME
• THE TEST MUST BE PERFORMED IN DUPLICATE S WITH THE TEST
AND CONTROL PLASMA AND AVERAGE VALUES OBTAINED
• REPEAT PROTHROMBIN TIME IN SECONDS
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8. CLINICAL CONDITIONS &
NORMAL VALUE
• PT IS DONE IN HAEMORRHAGIC CONDITIONS
• NORMAL VALUE – 14 +/- 2 seconds
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9. PROLONGED PT
• LIVER DISEASE,DUE TO DIMINISHED SYNTHESIS OF CLOTTING
FACTORS
• MASSIVE BLOOD TRANSFUSION DUE TO DILUTION OF PLASMA
CLOTTING FACTORS
FIBRINOGEN ABNORMALITY (Eg. HYPOFIBRINOGENEMIA)
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TIME
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10. CAUSES OF DECREASED PT
• VITAMIN K SUPPLEMENTATION
• FRESH FROZEN PLASMA TRANSFUSION
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12. activated PARTIAL
THROMBOPLATIN TIME
THE TIME REQUIRED FOR CLOTTING OF CITRATE PLASMA IN A
GLASS TUBE AFTER THE ADDITION OF CEPHALIN ,PLASMA AND
CALCIUM
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13. MATERIALS REQUIREMENTS
• WATERBATH
• STOPWATCH
• CHLOROFORM EXTRACT OF BRAIN (PHOSPHOLIPIDS)
• CALCIUM CHLORIDE - 0.025M
• TEST TUBE
• CONTROL PLASMA
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14. PRINCIPLE
• THE PLATELET SUBSTITUTE (CEPHALIN) IN THE FORM OF
PARTIAL THROMBOPLASTIN (PREPARED FROM RABBIT BRAIN
AS CHLOROFORM EXTRACT)
• WHEN MIXED WITH TEST PLASMA AND CALCIUM IONS,CLOT
FORMATION TAKE PLACE
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TIME
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15. PROCEDURE
PIPETTE 0.2ml OF BRAIN EXTRACT IN A SMALL TEST TUBE
ADD 0.2ml OF PLASMA
ADD 0.2 ml OF PRE- WARMED (AT 37 c) CALCIUM CHLORIDE START
STOP WATCH
IN THE TUBE TILL THE FIBRIN CLOT APPEARS
NOTE THE TIME
REPORT THE TIME
REPORT THE PROCEDURE FOR CONTROL SERUM
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16. • THE VOLUME OF THE CONTROL SHOULD BE WITHIN THE
NORMAL RANGE,OTHERWISE CHECK THE REAGENTS
• THIS TEST SHOULD BE PERFORMED IMMEDIATELY AFTER THE
BLOOD COLLECTION BY A DISPOSABLE PLASTIC SYRINGE
PREFERABLY IN PLASTIC TUBE
• NORMAL RANGE: 60 TO 80 SECONDS
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17. ABNORMAL PTT
• INDICATES STAGE 1,COAGULATION DEFECTS THAT IS
DEFICIENCY OF ONE OR MORE FACTORS –XI,XII,IX,V,II
• 1.PRESENCE OF INHIBITORS OF COAGULATION SUCH AS
FACTOR INHIBITORS FOUND IN SLE – SYSTEMIC LUPUS
ERYTHEMA (AN INFLAMMATORY DISEASE CAUSED WHEN THE
IMMUNE SYSTEM ATTACKS ITS OWN TISSUES)
• DIC - DISEMMINATED INTRAVASCULAR COAGULATION(BLOOD
CLOTS AND BLEEDING,POSSIBLY FROM MANY SITES IN THE
BODY)
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18. PREVIOUS YEAR QUESTIONS
• APTT (3MARKS) SEPTEMBER 2014
• NAME VARIOUS ANTICOAGULANTS USED IN BLOOD BANK
AND DISCUSS VARIOUS ROUTINE HEMATOLOGICAL
INVESTIGATIONS DONE IN BLEEDING DISORDERS AUG/SEP
2009
• PT (5 MARKS) QUESTION BANK /MARCH 2013
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