Bleeding Time by Ivy Bleeding Time Test, by Duke Method, CLOTTING TIME (Lee-White method) .

Bleeding Time by  Ivy Bleeding Time Test, by Duke Method,
CLOTTING TIME (Lee-White method) ,

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TESTS FOR COAGULATION FUNCTION

Bleeding Time

Bleeding time measures the time required for the blood to stop flowing after a standardized capillary puncture. This depends on the number and function of platelets and capillary integrity.

Method 1: Ivy Bleeding Time Test

• Place a blood pressure cuff on the upper arm and inflate it to 40 mm Hg.

• Clean the area of the forearm below the antecubital fossa with 70% alcohol. There should be no superficial veins in the area selected.

• Make two skin punctures in rapid succession, each 3 mm deep, using disposable lancets.

•  Start the stop-watch as soon as bleeding starts. Wipe off the blood at 15 seconds intervals by touching lightly with a blotting paper.

• Record the time is taken for the blood to stop flowing in both the punctures and determine the meantime. Remove the blood pressure cuff and cover the puncture sites with plaster.

Normal range 2-6 minutes. Values between 6 and 10 minutes are considered borderline and the test should be repeated. However, owing to variations in techniques and patients population, each laboratory should establish its own normal range.

Method 2: Duke Method

• Clean and ear lobe or a fingertip (or heel, in an infant) with 70% alcohol.

• Make a 3mm deep puncture using a disposable lancet

• Start the stop-watch as soon as bleeding starts.

• Blot the drops of blood in the same way as in method 1.

• Record the time at which bleeding stops. 

Normal range 0-6 minutes is considered normal. 

Interpretation Conditions associated with prolonged bleeding time include:

• Thrombocytopenia 

• Inherited or acquired platelet function defects. 

• Inherited plasma defects (e.g von Willebrand's disease, factor V deficiency)

• Vascular abnormalities. 

• Drugs. e.g. aspirin and antihistamine.

CLOTTING TIME (Lee-White method)

This test is a qualitative measurement of factors involved in the intrinsic pathway. Therefore, deficiency in the factors of the intrinsic pathway (I, II, V, VIII, IX. X. XI. XII) will affect the result. 

Principle The test is based on the fact that whole blood, when added to a foreign surface such as glass, will form a clot. The time required for the formation of a clot is a rough indication of the efficiency of the coagulation factors. 

Technique 

• Make a clean venepuncture with minimum trauma to the connective tissue (to avoid contamination with tissue thromboplastin).

• Start a stop-watch as soon as the blood enters the glass syringe. Draw 4.0 ml of blood and deliver Iml each into 4 glass test tubes previously warmed to 37°C.

• Place the tubes immediately at 37°C water bath

• At the end of 1 minute, gently tilts one tube to see if the blood is clotted.

• Continue tilting the tubes one after the other at one-minute intervals till one of them can be tilted at an angle of 90°C without the blood flowing out.

• Note the time.

• Continue with the remaining tubes and take the average of the clotting time in all the four tubes.

Note

If plastic or siliconized syringe is used, the stopwatch is started after adding blood to the glass tubes.

Normal range 5-10 minutes. Interpretation The clotting time is prolonged if there is a marked deficiency in one of the coagulation factors of the intrinsic pathway.

Note

If plastic or siliconized syringe is used, the stopwatch is started after adding blood to the glass