BT, CT, PT, INR - Pathology - Nursing

Course: 2nd year Nursing

Faculty: Pathology

Kanachur Institute of Medical Sciences

1. Bleeding Time Clotting Time Prothrombin Time INR Dr. Salman Ansari Dept. of Pathology Kanachur Institute of Medical Sciences

2. Contents BT CT PT, INR

3. Bleeding Time

4. Bleeding Time Test used to diagnose bleeding disorders Measures how fast the bleeding stops It assesses platelet function Methods : Duke’s method Ivy’s method

5. Duke’s method Equipment : lancet, cotton, filter paper, spirit, stopwatch Procedure : Sterilise finger tip with spirit, allow to dry Prick sufficiently deeply, so blood comes out without squeezing Note the time when bleeding starts

6. Mop the blood by touching the finger tip with the filter paper Repeat every 15 seconds, each time using a fresh portion of the paper till bleeding stops Note the time

7. Normal BT : 1-9 minutes Prolonged BT seen in : Thrombocytopenia Platelet disorders Coagulation disorder; Von Willebrand disease Blood vessel disorders

8. Clotting time

9. Clotting time It is the time required for the blood to coagulate It is a test of coagulation factor function Methods : Capillary tube method(Wright’s method) Venepuncture method(Modified Lee and White method)

10. Capillary tube method Equipment : capillary tube, cotton, spirit, lancet, stopwatch Procedure : Sterilise finger tip with spirit, allow to dry Prick sufficiently deeply, so blood comes out without squeezing Note the time when bleeding starts Touch the blood drop using one end of the capillary tube tilted downwards

11. It gets filled via capillary action After 2 minutes, start breaking off small lengths of the tube, at intervals of 15 seconds and look for a fibrin thread between the snapped ends Note the time when the fibrin thread is first seen

12. Normal CT : 3-10 minutes Prolonged CT is seen in : Hemophilia Vitamin K deficiency Liver diseases DIC Overdosage of anticoagulants

13. Prothrombin time

14. Prothrombin time Measures the time taken by plasma to clot Test of the extrinsic pathway of coagulation PT reveals deficiency of factors 2, 5, 7, 10 or fibrinogen

15. Procedure Blood sample collected and anti-coagulant added(oxalate) Calcium and tissue factor is added to test CT, which activates extrinsic pathway of coagulation Calcium and tissue factor activates clotting factors to convert prothrombin into thrombin Time taken for blood to coagulate is recorded - this is prothrombin time

16. Normal PT : 9-12 seconds Prolonged PT seen in : Deficiencies of clotting factors, like factor VIII(hemophilia A), factor IX(hemophilia B), factor XI(hemophilia C) VWD

17. INR

18. International Normalised Ratio(INR) Used to assess therapeutic effect of warfarin It is the ratio of PT of the patient to normal control Normal values : In healthy people - <1.1 Patients taking warfarin - 2.0-3.0

19. References: Dr. Purnima S. Rao - Textbook of Pathology & Genetics For Nursing Questions: [email protected]