Indications to perform this test:  This is a simple clinical procedure used to evaluate the primary clotting system of a patient suspected to have a primary hemostatic disorder.  Primary bleeding disorders are either due to inadequate platelet numbers or improperly functioning platelets, but do not involve the coagulation factors.  Coagulation factor deficiencies will not cause a prolonged buccal mucosal bleeding time.

The Procedure:  This test is performed in small animals by making a small incision with an automated incision making device on the inside of the upper buccal mucosa.  The clock is started as the small wound begins bleeding.  The blood is blotted off of the skin with a piece of filter paper.  When the bleeding has ceased due to the formation of a primary clot, the time is stopped.  This total period of time represents the buccal mucosal bleeding time or the BMBT.  While the test is necessarily imprecise, it does give a crude evaluation of the ability of the platelets to form an initial plug in a wound.  On horses, this test is usually performed on the forearm rather than the buccal mucosa.

Interpretation of prolonged mucosal bleeding times:

• Severe thrombocytopenia:  A CBC is a more efficient way to determine the presence of a thrombocytopenia.

• Congenital platelet abnormalities:  Such as vonWillebrand's disease and others.

• Acquired platelet function defect

• Disseminated intravascular coagulation (DIC)

For  more information . . .

• Veterinary Laboratory Medicine, Duncan, Prasse, and Mahaffey page 79-80.
• Veterinary Laboratory Medicine, Interpretation & Diagnosis.  Meyer & Harvey, pages 124.