Determination Of Blood Clotting Time (Practical)


Whenever a great blood vessel ruptures bleeding continues. In a few minutes blood looses its fluidity and sets into a semisolid mass. The mass is referred as clot and the phenomenon as coagulation.
Clotting time is defined as the time interval in between onset of bleeding and appearance of semisolid mass i.e. clot. Normal value of clotting time is 3-4 minutes. Clotting time is determined using two methods viz. Capillary glass method and Wrights Coagulometer.
The aim of the experiment is to determine the clotting time of the subject.


Spirit, cotton, needle, capillary tube, stop watch.


Capillary glass method:

  1. The finger tip of the subject is sterilized and a bold prick is made in the fingertip with a sterilized needle to have free flow of blood.
  2. The blood coming out of the puncture is sucked into a capillary glass tube of 15 cm long.
  3. Then the tube is kept undisturbed horizontally for about 1-2 minutes.
  4. A small bit of the glass tube is broken off every 30 seconds until a fine thread of clotted blood appears while the capillary tube is broken.
  5. When the thread appears the stop watch is stopped. This gave us the clotting time. The period in between appearance of blood in finger and formation of clot was taken as clotting time.


The clotting time of the subject was found to be  ____________ minutes.


Hematology, Practical Human Anatomy And Physiology, by ZILMS.COM