Bleeding time and clotting time

Bleeding time and clotting time

1. BLEEDING TIME AND CLOTTING TIME SUNIL KUMAR.P Dept. of Haematology SJMCH, Bangalore 1 SUNIL KUMAR.P

2. BLEEDING TIME First functional platelet evaluation test Introduced by duke in 1900 Used to detect defects in primary hemostasis Used as a screening test for vascular disorders as well as platelet function test. 2 SUNIL KUMAR.P

3. PRINCIPLE A standardised incision is made on the volar surface of the forearm The time the incision bleeds is measured Cessation of bleeding indicate the formation of haemostatic plug Depends on the adequate no: of platelets and on the ability of the platelets to adhere to the subendothelium . 3 SUNIL KUMAR.P

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5. METHODS Standard template method Dukes method Ivy’s method Copley and lalitch method 5 SUNIL KUMAR.P

6. IVY’S METHOD REQUIREMENTS: BP cuff Disposable lancet Stop watch Filter paper Spirit/alcohol 6 SUNIL KUMAR.P

7. PROCEDURE Clean the inner aspect of the fore arm Place a BP cuff on the upper arm , inflate to 40 mm of mercury. Select an area on the volar surface which is devoid of veins Should be performed at room temperature. A disposable lancet with a point of about 3mm /No.11 bard parker surgical blade is taken. 7 SUNIL KUMAR.P

8. Three skin punctures 1mm deep and 3 mm long are made. Stopwatch is started as soon as the bleeding starts in each wound. Using the edge of a filter paper ( whattman No:1) , blot the blood accumalated over the wound The time from which incision was made to the time at which the bleeding stops to stain the filter paper is taken. 8 SUNIL KUMAR.P

9. The average of the 3 bleeding time is taken . The BP cuff is removed. The puncture wounds are cleaned Sterile bandage applied The longer of the duplicate bleeding time will be the most accurate one. Longer bleeding time-puncture of superficial veins 9 SUNIL KUMAR.P

10. If bleeding continues more than 15 min-apply pressure Repeat the bleeding time on other arm. Report-greater than 15 min. Reports correlated with platelet count and finger prick smear. Reference range-2-7’ 10 SUNIL KUMAR.P

11. ADVANTAGE Standardised method Bleeding time more accurate Normal BT-3-8’. 11 SUNIL KUMAR.P

12. LIMITATIONS Not a very reliable test. The puncture wound may close before the cessation of bleeding. 12 SUNIL KUMAR.P

13. STANDARD TEMPLATE METHOD More standardised method Uses a glass or plastic template Allows the lancet to make a cut-11 mm long and 1mm deep. 13 SUNIL KUMAR.P

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19. ADVANTAGES Test is very sensitive and reproducible Detects even minor alterations in platelet function. 19 SUNIL KUMAR.P

20. DUKE’S METHOD Easy to perform Requires minimal equipment Requirements- alcohol,sterile lancet,stopwatch,filter paper 20 SUNIL KUMAR.P

21. PROCEDURE Clean the ear lobe with alcohol sponge Infants-heel of foot Hold a glass slide behind the ear lobe Make a deep puncture with sterile lancet. Start the stop watch Discard the glass slide Using filter paper blot the drop of blood coming out from incision. 21 SUNIL KUMAR.P

22. When bleeding ceases stop the stop watch. Count the number of drop on the filterpaper Multiply by 30 sec Report the closest minute If the cut bleeds more than 10 ‘,discontinue the test 22 SUNIL KUMAR.P

23. ADVANTAGES The ear lobule contain abundant subcutaneous tissue and is vascular. Flow of the blood is quite good Normal bleeding time-3-5’ DISADVANTAGE Difficult to get a standardised wound 23 SUNIL KUMAR.P

24. COPLEY AND LALITCH METHOD Clean the finger Make a puncture wound 6mm deep Immerse the wound in sterile physiological saline warmed to 37 o Laeve it until there is no free flow of blood The BT measured from the moment of the wound to the cessation of bleeding. 24 SUNIL KUMAR.P

25. VARIABLES AFFECTING BT Anemia prolongs the bleeding time. Patients with thrombocytopenia(<100×10 9 /L) Will have increased BT. Aspirin,pencillin,cephalothin prolongs BT Pediatric pts and neonates –smaller incisions are required.pressure -20 mm of Hg. 25 SUNIL KUMAR.P

26. CLINICAL SIGNIFICANCE Prolonged BT in Thromboctytopenia Disorders in platelet fn- thrombasthenia,storage pool disease,Bernard – Soulier syndrome Afibrinogenemia Severe hypofibrinogenemia Vascular disorders Aspirin 26 SUNIL KUMAR.P

27. Aplastic anaemia A/c leukkemia Liver diseases Von Willibrand disease DIC Vascular abnormalities -Ehlers danlos syndrome Severe deficiency of factor V or XI 27 SUNIL KUMAR.P

28. WHOLE BLOOD CLOTTING TIME The time it takes for whole blood , drawn from a vein and immediately placed in a container to clot. It measures all stages of intrinsic coagulation It is not a very sensitive method Avoid contamination with tissue fluid. 28 SUNIL KUMAR.P

29. METHODS Venepuncture method-Modified lee and white method Capillary method Heparin retarded blood coagulation time 29 SUNIL KUMAR.P

30. VENEPUNCTURE METHOD Sample collection 2 SYRINGE TECHNIQUE-avoid interference from tissue fluid Draw 1 ml of blood into first syringe Without disturbing the position of the needle 2 nd syringe attached. 5ml of blood drawn 30 SUNIL KUMAR.P

31. EQUIPMENTS Cotton wool,surgical gauze soaked in alcohol,plastic syringe Test tube-acid washed(10ml) Water bath -37 c. Stop watch 31 SUNIL KUMAR.P

32. PROCEDURE 2ml of venous blood collected quickly Start the stop watch as soon as the blood enters the syringe Fill each of the tube to 1 ml mark. Plug the tube and place them in water bath at 37 c. After 5’ tilt the first tube at an angle 45 c.(room temp-10’) If not clotted return to water bath 32 SUNIL KUMAR.P

33. Examine at an interval of 30 sec When the blood is clotted it can be tilted at an angle of 90 c without spilling the contents. As soon as blood is clotted,immediately examine the second tube. Stop the stop watch and note the time. Coagulation time is the clotting time of the second tube. 33 SUNIL KUMAR.P

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35. ADVANTAGE More accurate and standard method Test can be run with control DISADVANTAGE Only a rough method There can be contamination of syringe /tubes 35 SUNIL KUMAR.P

36. NORMAL VALUE DEPENDS ON THE METHOD USED Normal value-8-15’ If 10 min inc done-20 -22 min Value<8min-contamination with tissue fluid / hypercoagulability . 36 SUNIL KUMAR.P

37. SOURCES OF ERRORS Faulty technique Inappropriate volume of blood Faulty venepuncture Air bubble entering the syringe Diameter of the glass tube should be uniform Always use clean glass wares and plastic syringe Vigorous agitation should be avoided. 37 SUNIL KUMAR.P

38. CAPILLARY METHOD PRINCIPLE-puncture the skin,blood is taken to a plain capillary tube and stop watch started. Formation of fibrin strings is noted by breaking the capillary tube at regular intervals. The time taken for the first appearance of the fibrin string is noted. 38 SUNIL KUMAR.P

39. EQUIPMENT Disposable lancet Capillary tubing10-15 cm length and 1.5 mm diameter without anticoagulant 39 SUNIL KUMAR.P

40. PROCEDURE Warm up the finger for skin puncture Make an incision with a sterile disposable lancet to depth of 3mm. As soon as blood is visible- start the stop watch. Wipe off the first drop of blood Allow 2 nd drop of blood to flow to capillary tube . 40 SUNIL KUMAR.P

41. After 2’ break off the capillary tubing,1-2 cm from the end. When a thin string of fibrin can be seen in between the broken end of the capillary tube,stop the watch and note the time Report the time 41 SUNIL KUMAR.P

42. DISADVANTAGE This method is insensitive This method is unreliable Capillary blood always contaminated with tissue fluid ADVANTAGE Can be performed when venous blood cannot be obtained NORMAL CT-1-5 min. 42 SUNIL KUMAR.P

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44. HEPARIN RETARDED BLOOD COAGULATION TIME REQUIREMENTS .004 mg per ml of isotonic saline. Venous blood freshly drawn in to syringe TECHNIQUE Add 1ml of heparin solution in a clean dry test tube in waterbath at 37 c Add 1ml of blood to this test tube and invert twice. A t the end of 12 min,tilt the tube gently at I min interval. Look for clot formation Normal range-20-35 min 44 SUNIL KUMAR.P

45. SIGNIFICANCE It appears to be the most valuable single test of coagulation. Test used to detect hypercoagulable and hypocoagulable states. Prolonged clotting time seen in deficiency states involving AHG,Plasma thromoblastin component, plasma thromboplastin activator. Also prolonged in pt with bone marrow depression and thrombocytopenia. 45 SUNIL KUMAR.P

46. ACTIVATED CLOTTING TIME Used to access heparin effects during cardiac surgery Negatively charged clotting cascade activators are used- celite,kaolin . Look for clot formation-either optical/electromagnetic method Normal value- celite -100-170 sec Kaolin-90-150 sec ACT MONITORS-HEMOCHRON ACT,HEMOTECH AUTOMATED ANTICOAGULATION TIMER. 46 SUNIL KUMAR.P

47. CLINICAL SIGNIFICANCE Only severe clotting factor deficiency can be recognised Prolonged CT more than 10’-pt subjected to more detailed test. Used to monitor heparin therapy. Can be due to the deficiency of plasma factors such as Antihemophiliac globulin,plasma thromboplastin,fibrinogen,prothrombin . Circulating anticoagulants 47 SUNIL KUMAR.P