Download Hemostasis and Coagulation

Bleeding time
 It is the time that elapses between the puncture of the
skin and the stoppage of blood oozing.
Introduction and principle
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A standarized puncture of the ear lobe is made
and the time need for bleeding to stop is recorded.
Cessation of bleeding indicates the formation of
haemostatic (platlet) plugs which are in turn rely on
an adequate number of platelets and the ability of the
platelets to adhere to the subendothelium and to form
aggregates.
Methods
 1-Duke test(the easiest to perform)
 2-IVY test
 3- Template test.
Duke Test
Material and Instruments
1-Sterile disposable lancet.
2- Stopwatch.
3-Circular test paper.
4- Alcohol prep pads.
Procedure
 1-The ear lobe is disinfected with alcohol sponge and
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allowed to dry .
2- A standardized puncture of ear lobe is then
made, using a sterile blood lancet.
3-The stopwatch is started at the moment of the
puncture.
4-Using a circular filter paper the blood is blotted
every 30 seconds without allowing the filter paper to
touch the wound.
 5- When the bleeding ceases, the stopwatch is
stopped and the bleeding time calculated as
 the number of blood spots on filter paper divided by 2
 Results:
 Normal range: 1-3 minutes, borderline times are 3-6
minutes.
Discussion:
What is the clinical significant of determining bleeding
time?
Coagulation (Clotting) time
 The coagulation time of whole blood is the time
required for a measured amount of blood to clot
under certain specialized condition.
 The aim:
 To determine clotting time.
Method
 Lee and White method
 Materials and Instruments
 1-water bath,37 C .
 2-glass test tubes, 13*100 mm.
 3-stopwatch.
 4-plastic syringe (10ml) and 20 gauge needle.
 5- fresh whole blood, 4 ml.
Procedure
 1-Lable three test tubes with the subject (patient)
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name, and number them,1,2 and 3.
2-Withdraw 4ml of blood from the subject.
3-Carfully place 1ml of the blood in the test tube 3,then
1ml in test tube 2, and finally, 1 ml in the test tube 1.
Start the stopwatch as soon as the blood is placed in
the tube 3.
4-Place the three tubes in a 37C water bath.
5-At exactly 5 minutes, tilt test tube 1 gently to 45
angle. Repeat this step every 30 seconds until the test
 tube can completely be inverted without spilling the
contents( until the blood is completely clotted).
 6-Record the time it took for the blood in test tube 1 to
clot.
 7-Thirty seconds after the blood in test tube 1 is clotted,
proceed with test tube 2 and repeat the preceding steps,
tilting the test tube every 30 seconds until a clot is
formed. Record the results. Repeat this step for test
tube 3 as well.
 8-Since agitation and handling speed up the coagulation,
the coagulation time of test tube 3 is used to report the
result.
Results
 Normal range 5-11 minutes.
 Discussion
 1- How can you differentiate between purpura and
haemophilia?
 2-Test tubes are incubated in water bath at 37C.Why?
The difference between purpura and
haemophilia are:
Disease
Bleeding
time
pupura
increased
Haemophilia
normal
Clotting
time
normal
increased