BT CT HESS TEST CLOT RETRACTION TIME.pptx

BT CT HESS TEST CLOT RETRACTION

1. BLEEDINF TIME and CLOTTING TIME DEPT- M.Sc MLT( Haematology & Blood Transfusion)

2. Introduction Disorder of hemostastis are broadly divided into bleeding disorders and thrombotic disorders. Most bleeding disorders are caused by one of the three defects- A defect in platelet number or function A defect in platelet-vessel wall interaction A defect or deficiency in coagulation factor There are the certain laboratory tests which helps to diagnose the bleeding disorders

3. BLEEDING TIME Test assesses primary haemostasis Used as a screening test for disorders of platelet-vessel wall interaction Introduce by Duke in 1900. It measures the time required for bleeding to stop after a standardized superficial cut of the skin Normal bleeding time is between 2-6 minutes

4. METHOD The three method is commonly used: Duke’s method Ivy’s method Template methods Duke’s method - measures bleeding time following ear lob puncture. Is not advocated since it cannot be standardized and can cause a large local hematoma.

5. REQUIREMENTS Stopwatch Lancet Filter paper Glass slide Alcohol sponges METHODS Clean the ear lobe with alcohol and let it dry Hold the glass slide behind the ear lobe Pierce the ear lobe by a lancet against the glass slide Start the stop watch when the stab was made Bleeding of the wound should be allowed to proceed without pressure and blood is allowed to drop on the filter paper

6. The paper should be moved so that each drop will fall on fresh area When bleeding slows, the wound is touched gently with fresh area of the filter paper at 30 sec intervals. When blood no longer stains the filter paper, the watch is stopped and the time recorded. Normal value- The normal range is up to 6 mins Between 6-10 mins, the result are borderline Over 10 mins is definitely abnormal

7. Ivy’s method- Three standard puncture are made with a lancet on the volar surface of the forearm under standard pressure and the average time required for bleeding to cease from the puncture sites is measured. EQUIPMENTS- - Sphygmomanometer - L ancet - stopwatch - Filter paper

8. METHOD A sphygmomanometer cuff is wrapped around thee upper arm and inflated to 40 mm of Hg. The dorsal surface of the forearm is cleaned with 70% ethanol and allowed to dry Three puncture are made about 1mm deep and start a stopwatch soon after the puncture Blood oozing from the puncture wound is gently blotted with filter paper at 15 sec intervals

9. The timer is stopped when blood no longer stains the filter paper The time required for bleeding to cease from all the three puncture wounds is noted. The average time is reported as the bleeding time. Sterile adhesive strip is applied over the puncture. Normal range- Normal values are 1-6 mins More than 6 mins should be taken as abnormal

10. Template methods- it is a disposable blade fitted on to a holder made of plastic and is used for the test. the blade projects through the bottom so that the incision made through the slit is 9mm long and 1mmdeep Principle- a small skin cut of a standard size and depth is made and the oozing blood is wiped with a filter paper. Bleeding stops when the capillaries contract and platelet plug seals the vessel. Aantages ; Test is very sensitive and reproducible Detect even minor alterations in platelet function.

11. Procedure – Patient is made sit on a chair with an arm rest, so that the forearm is steady and exposed The skin of the forearm is cleaned with alcohol and allowed to dry Sphygmomanometer cuff is tied to the upper arm and the cuff is inflated to 40 mm Hg A site on the forearm is selected away from the superficial veins Place the template 5cm distal to anticubital crease One cut is made using a smooth rapid movement with the template Immediately after the incision, a stop watch is started

12. Another cut is made 1.5-2 cm away from the first one and another stop watch is started The blood oozing from the sides of the cut is blotted with filter paper, every 30 sec until bleeding stops Time at which bleeding stops is noted for both cuts Place a butterfly adhesive bandage over the site of puncture to avid scarring Average of the two readings is the bleeding time for the patient. NORMAL RANGE: 2-9minutes

13. USES- Test is prone to problems of reproducibility, sensitivity and specificity This test evaluates the defects of primary haemostasis

14. CLOTTING TIME Clotting time measures the time required for the blood to clot. It measures all stages of intrinsic coagulation Normal range is between 8-15 minutes Method- - Lee and white method (venepuncture method) Capillary method

15. Lee and White method- It measures the time taken for the fresh blood to clot NORMAL VALUE : 4-11 minutes Equipments- Cotton wool, surgical gauze, syringe Test tubes Water bath-37 degree Celsius Stop watch

16. PROEDURE: 2ml of venous blood is collected with aseptic precaution Label 2 test tubes as no. 1 and 2 and keep in a water bath at 37 Degree celsius After 3mins tilt the first tube at an angle 45 Degree If not clotted return to water bath Examine at an interval of 30 sec When the blood is clotted it can be tilted at an angle of 90 Degree without spilling the contents. As soon as the 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.

17. CAPILLARY METHOD NORMAL VALUE: 1-5 minutes Equipments- Disposable lancet Capillary tubing

18. Procedure Clean the finger tip with a cotton spirit and wait for a sec to dry. Warm up the finger for skin puncture Make an incision with a sterile disposable lancet to depth of 30mm. As soon as the 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 After 2 mins break off the capillary tubing 1-2cm 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.

19. HESS TEST Also know as tourniquet test or Rumpel-Leede test or capillary fragility test. This test measures the ability of capillaries to withstands the increased stress Normal: 0-5

20. Inflate the blood pressure cuff on the upper to a point midway between the systolic and diastolic pressure for 5mins Release and make an imaginary 2.5cm square or 1 inch square just below the cuff at the antecubital fossa Count the number of petechia inside the box. Presence of more than 10 petechia is considered a positive test. METHOD

21. Positive test

22. CLOT RETRACTION TIME DEFINITION- The time required following for withdrawal of a blood clot to completely contrast and express the serum entrapped within the fibrin net. usually completed in 18-24 hours. Clot retraction depends on the number of platelets in the specimen.

23. PRINCIPLE After the coagulation of blood, the clot under the action of thrombasthenin undergoes contraction and starts retracting within one hours. The clot shows 50% retraction in 2 to 4 hours. This process is completed in 18-24 hours with separation of serum. Subsequently, the fibrin clot dissolves due to fibrinolysis and the RBCs sink to the bottom. Clot retraction is dependent on normal platelet number, platelet function, concentration of fibrinogen and the activity of the fibrinolytic pathway.

24. PROCEDURE Place a tube containing blood in a water-bath at 37 Degree Celsius. Examine the clot after 1 hour and after 24 hours. Note the size, consistency of the colt and the nature of retraction. Continue observation of clot for 72 hours to assess the clot lysis .

25. NORMAL VALUE Normal clot retraction shows more than 50% of serum separated at the end of 24hours. A normal clot is firm, rubbery, elastic and not easily broken

26. INTERPRETATION Absent or reduced clot retraction is seen in- Fibrinogen deficiency Thrombocytopenia thrombasthenia

27. REFERECES Daice and lewis Practical Hematology Essential of Hematology by Shirish M Kawthalkar. Essentials in HEMATOLOGY and CLINICAL PATHOLOGY- Nayak Rai Gupta HEMATOLOGY for Students and Practitioners- Ramnik Sood

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