This document summarizes various tests used to assess the coagulation profile and integrity of the haemostatic mechanism. It describes tests such as bleeding time, clotting time, prothrombin time, partial thromboplastin time, activated partial thromboplastin time, thrombin time, and plasma recalcification time. These tests measure different aspects of the coagulation cascade and help identify bleeding disorders or conditions where coagulation may be prolonged, such as liver disease, vitamin K deficiency, and anticoagulant overdose. Determining the coagulation profile is important before procedures like surgery to assess a patient's bleeding risk.

1. Coagulation Profile
Dr. Anand T. More
Department of Physiology
D. Y. Patil Medical College, Kolhapur

2. Introduction
• This tests are determined to assess the integrity of haemostatic
mechanism.
HAEMOSTASIS –
Spontaneous arrest or prevention of bleeding by
physiological process is called haemostasis.

3. Series of events involved in haemostasis

4. Bleeding Time
• Bleeding time is defined as time interval between puncture to the
blood vessel to the stoppage of bleeding.
Methods of determination of bleeding time-
I) Duke Method
II) Ivy Method

5. Duke Method
[ 30 sec interval ]
5 blots (4 blood blots+ 1 blank blot) x 30 sec = 2mins 30 sec

6. Ivy Method

7. Clotting Time
• Clotting time is defined as time interval between puncture to the
blood vessel to the formation of fibrin thread.
Methods of determination of clotting time-
I) Capillary tube method
II) Lee - White method

8. Capillary tube method
iv
i ii iii

10. Lee - White method
Principle
Venous blood is collected in clean glass tube without any anticoagulant.
The time taken by blood to clot at 37 degree Celsius is noted as clotting
time.
Normal Value – 5 to 12 minutes

11. Conditions where BT & CT are altered
Bleeding time is prolonged in :
i) Thrombocytopenia - ↓ in platelet count
ii) Thrombasthenia – Platelet count is normal but they are functionally
abnormal
iii) Von Willebrand disease – Platelet defect combined with factor VIII
deficiency.
iv) Purpura – It is a condition with various manifestation & different
causes, characterized by capillary abnormality resulting in
haemorrhages into the skin, mucous membrane, internal organ &
other tissues.

12. Clotting time is prolonged in :
i) Classical Haemophilia (Haemophilia A)
ii) Vitamin K deficiency (Factor II, VII, IX & X)
iii) Christmas disease (Factor IX)
iv) Liver diseases – Hepatitis, cirrhosis
v) Anticoagulant overdose

13. Clinical significance of determining BT & CT
It is very important to know BT & CT in the following conditions :
i) Before surgery (Fitness test)
ii) Before any biopsy (especially liver or bone marrow biopsy)
iii) Before putting any patient on anticoagulant therapy
iv) Aspirin or any other NSAID (Inhibit enzyme cyclooxygenase which
leads to inhibition of platelet aggregation)

14. Other tests for bleeding disorders
Capillary Fragility Test
Principle
This test measures the ability of the capillaries to withstand increased
stress.
Petechiae appear in the forearm of the subject when the blood
pressure cuff in the arm is inflated to a maximum pressure of 100mm
Hg for about 5 minutes.

15. Platelet Aggregation Test
Principle
An aggregating agent is added to a suspension of platelets in plasma
and the response is measured turbidometrically as a change in the
transmission of light by an instrument called the aggregometer.

16. Platelet Adhesiveness Test
Principle
This test measures the ability of platelets to adhere to a glass surface.
When anticoagulated blood is allowed to pass at a constant rate
through a plastic tube containing glass beads, some platelets adhere to
the glass beads.
The percentage difference of the platelet count prior to & after passing
through the glass bead column indicates the functional status of
platelets.

17. Clot Retraction Time
Principle
Blood clots when collected in a glass tube without any anticoagulant.
The clot begins to retract (after blood has clotted) within 30 seconds, &
about 50% at the end of 1 hour.
At the end 18-24 hours the clot should have retracted completely.

18. Clot Lysis Time
Principle
The clot is lysed due to fibrinolysis, which is a natural process.
Due to lysis the clot becomes fluid & red cells sink to the bottom of the
test tube.

19. Prothrombin Consumption Test
Principle
This test determines the amount of prothrombin present in the serum
after clot formation.

20. Prothrombin Time (PT)
Principle
A preparation of rabbit brain emulsion (which contains tissue
thromboplastin) is added to plasma in the presence of calcium. This, in
the presence of factor VII triggers stage 2 of the coagulation
mechanism, & the clotting time is recorded after the addition of
calcified thromboplastin to the plasma
Normal Value - 12-16 seconds

21. Partial Thromboplastin Time (PTT)
Principle
The platelet substitute, in the form of partial thromboplastin, is
prepared from rabbit brain as chloroform extract. When mixed with
test plasma containing excess of calcium, it leads to clot formation.
Normal Value - 60 to 80 seconds

22. Activated Partial Thromboplastin Time (aPTT)
Principle
The platelet substitute, in the form of partial thromboplastin is
prepared from rabbit brain. This is incubated with a contacting agent
(kaolin) to provide optimal activation of the intrinsic coagulation
factors. The clotting time is determined after the addition of excess of
calcium.
Normal Value – 25 to 40 seconds

23. Thrombin Time (TT)
Principle
Thrombin (commercially available) is added to the plasma along with
calcium & the clotting time is determined.
Normal Value – 15-20 seconds

24. Plasma Recalcification Time (PRT)
Principle
When excess of calcium is added to the citrated plasma, clotting
occurs. Because platelet factor III is also involved in clotting through the
intrinsic pathway of coagulation, the clotting occurs in a shorter time in
platelet rich plasma than in platelet poor plasma.
Normal Value –
Platelet rich plasma - 100 to 150 seconds
Platelet poor plasma – 135 to 240 seconds

25. Source
• G. K. Pal Textbook of practical physiology
• A. K. Jain Manual of Practical physiology
• Net source

26. Thank You