EXPERIMENT NO. 03
“TO DETERMINE THE BLEEDING TIME OF A SUBJECT”
Requirements:
Sterile needles, spirit, cotton, filter paper, stop watch
Principle:
The bleeding time test is useful tool to test for platelet plug formation and capillary integrity. Occasionally,
the bleeding time test will be ordered on a patient scheduled for surgery.
Theory:
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Bleeding time: it is the time interval between skin puncture (coming out of blood from vessel) and
cessation of flow of blood.
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Factors affecting bleeding time: Physical size and shape of injury, the vascularity, endothelial
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smoothness and elasticity of blood vessels, capillary contractility, sealing by platelets, number of
thrombocytes (blood platelets) etc.
Significance of test: Although this test is usually performed on patients with a personal or family history
of bleeding disorders, it’s also useful-along with a platelet count for preoperative screening. The test is
usually not recommended for patients with a platelet count of less than 75,000/ul.
Procedure:
Two procedures are currently in use for determining the bleeding time: the Duke method and the Ivy
method.
Duke’s method:
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Keep ready filter paper. Wash the hands properly and allow to dry them.
Sterilize the fingertip with spirit and allow it to dry.
Make a deep puncture about 3-5 mm depth and immediately start the stop watch.
Blot drop of blood from prick on filter paper serially in a row 30 seconds intervals till there is no stain on
filter paper i.e. when blood stops oozing, stop the stop watch.
5. Count the spots of blood on filter paper.
6. Calculate bleeding time by multiplying the number of blood spots with 30 seconds and converting them
into minutes.
7. Compare the result with normal bleeding time.
Normal bleeding time: 2 to 6 min
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IVY method:
1. A blood pressure cuff is used to maintain constant pressure within the capillaries to help standardize the
procedure. The cuff is inflated to 40 mm Hg on the upper arm to control capillary tone and to improve
the sensitivity and reproducibility.
2. The forearm is bleeding time site used.
3. A sterile, disposable blood lancet is used and the length of time required for bleeding to cease is
recorded.
4. The greatest source of variation in this test is largely due to difficulty in performing a standardize
puncture. This usually leads to erroneously low results.
Normal values: 5 to 11 minutes by this method.
Observation:
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Result:
Bleeding time of one’s blood is ______ min _______ sec.
Precautions:
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Be sure to maintain a cuff pressure of 40 mm Hg throughout the test.
If the bleeding does not diminish after 15 minutes, discontinue the test.
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Abnormal Findings:
prolonged bleeding time may indicate the presence of disorders associated with thrombocytopenia, such as
Hodgkin’s disease, acute leukemia, disseminated intra vascular coagulation, hemolytic disease of the
newborn, Schonlein-Henoch purpura, severe hepatic disease (cirrhosis, for example), or severe deficiency
off actors I, II, V, VII, VIII, IX, and XI. Prolonged bleeding time in a person with a normal platelet count
suggests a platelet function disorder (thrombasthenia, thrombocytopathia) and requires further
investigation with clot retraction, prothrombin consumption, and platelet aggregation tests.
Discussion:
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Source of Errors:
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VIVA related questions:
1. When the patient is having a fever, is there any change in the bleeding time? If so give one reason.
2. If the patient has less blood, what is effect in the value of bleeding time?
3. Does the bleeding time depend upon whether the subject is fat or thin?
4. List two conditions in which the bleeding time could be prolonged.
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WORK PAGE
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