Aim: To determine the bleeding time of a patient.
Theory: The time required for complete stopping of blood flow from the punctured blood vessels is called the bleeding time. Normally it is 1-3 minutes for a normal human’s blood. Normal clotting time and bleeding time values differ because bleeding time is the time for stopping bleeding by the formation of fibrin network on the surface of punctured skin; that is it is the surface phenomenon. But the clotting time is the time for clotting the whole blood, collected in the capillary tube; therefore it is a volume phenomenon. For this reason, clotting time is more than the bleeding time, when determining by conventional methods.
Clinical significance: It plays a significant role in:
i) to study haemorrhagic disorders.
ii) to study the coagulation defects
iii)to have an idea about the platelets count of the patient. Bleeding time is prolonged in few disorders like vascular lesions, platelet defect, severe liver disease, uremia and anti-coagulant drug administration.
Requirements: Sterilized needle, filter paper, cotton, spirit, and stopwatch.
Procedure (Duke’s method): The finger of a subject is sterilized with spirit and pricked with a sterilized needle. Time of pricking is noted. Take the stain of the punctured point on a filter paper for 30 seconds and keep taking the stain of blood in 20-second intervals until the bleeding stops. The time of no stain has come is noted properly; it is the bleeding time of the subject.
Precaution: Following precautions should be enforced
i) Needle should be sterilized.
ii) A fain stain of blood should not be avoided.
iii) Time should be noted properly.