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Coagulation

Coagulation laboratory tests

Bleeding time


Reviewer: Jeremy Parsons, M.D. (see Reviewers page)
Revised: 20 June 2012, last major update June 2012
Copyright: (c) 2002-2012, PathologyOutlines.com, Inc.

General
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● A relatively nonspecific and nonsensitive test of platelet function, whose use is declining
● This test should usually be avoided, particularly if definitive testing, such as a von Willebrand panel is available
● Preoperative bleeding time does NOT predict surgical bleeding
● Test is affected by use of aspirin or other NSAIDs, patients should abstain from their use for 1 week prior to testing
● Test is also affected by how incision is made (very difficult to standardize)

Procedure:
● Place blood pressure cuff on arm at 40 mm Hg
● Then trained technologist makes a small incision on patientís arm, blots the blood gently every 30 seconds with filter paper, without touching the clot, to see if bleeding has stopped and records the time when it stops
● Then apply bandage

Duke bleeding time:
● Uses earlobe or fingertip pierced with lancet

Ivy bleeding time:
● Blood pressure cuff at 40 mm Hg on arm, and forearm cut by lancet

Mielke (template) bleeding time:
● Template placed on skin with spring loaded blade that cuts through template, to standardize the size and depth of cut
● More reproducible than standard bleeding time but still quite variable

Reference range:
● Varies, sample range is 1.5 to 9.5 minutes (less in newborns)

Prolonged values:
● Platelet count less than 100K, low hemoglobin, use of aspirin or other platelet inhibitors
● Also von Willebrandís and other hereditary platelet disorders, uremia

Additional references
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Blood 1991;77:2547

End of Coagulation > Coagulation laboratory tests > Bleeding time


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