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The Bleeding time is no
longer routinely available at MCL. Contact Core Lab (903-3946) for more information.
The following is background on the test.
The bleeding time test is approximately 170 years old and was developed even
before platelets were recognized as normal blood elements. The test was used
to evaluate patients who presented with purpura. Current thinking is that the
test evaluates platelet function, provided that the platelet numbers are
adequate. There are a few reports of prolongation in coagulation factor
deficiencies and with patients on heparin.
The test has very poor sensitivity. For example, the test will detect only
27% of patients with von Willebrand’s syndrome (whereas symptoms alone have a
sensitivity to von Willebrand’s of 65%). To investigate bleeding, take a good
history and use this test as part of a battery of tests.
Our reference range is 1-9 minutes but given a positive history of bleeding,
be suspicious in the borderline area ( 7 min.). The test lacks sensitivity
therefore, you should fully investigate all abnormal findings. It is very
difficult to define false positives as many bleeding tendencies are never
fully explained with today’s models.
Evaluations of the bleeding time indicate that you should not use the test:
*for preoperative screening.
*to rule out a bleeding disorder (for example: to prove child abuse).
*to clear a patient for surgery given clinical evidence of bleeding, other
laboratory abnormality(ies) or a positive history of bleeding.
The test is simply too insensitive and misses over 3/4ths. of bleeding
disorders due to platelet dysfunction.
The bottom line? As originally intended, use this test to investigate
purpura. Do not use the test to predict bleeding nor to justify other
procedures. Normal results are practically meaningless. A good history has
been shown, repeatedly, to be more sensitive to bleeding disorders than any
hemostatic screening test.
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