Overview
- Small vessel injury (eg incision in buccal mucosa) plugged by platelets and with minimal need for functional clotting cascade provides assessment of primary hemostasis, ie platelet and vessel function.
- Patients with coagulation defects such as hemophilia A or B have a normal BMBT since the bleeding stops in the expected time owing to the formation of platelet plugs. Note, since the platelet plug is not stabilized by fibrin strands, the incision is prone to re-bleed if traumatized later.
Uses
Alone
- Simple test of adequate platelet number and function.
Should avoid using this test to diagnose low platelet number - should perform smear for platelet count first.
- Also tests normal vessel reaction.
Vascular abnormalities are rare.
In combination
- With prothrombin time
and partial thromboplastin time : to assess primary and secondary hemostasis. - With platelet count and measurement of anti-platelet antibody titer : enables investigation of platelet dysfunction.
Anti-platelet antibody not routinely available in UK.
Result data
Normal (reference) values
- Normal : <5 min.
- Usually : 1-3 min.
Abnormal values
- Prolonged BMBT : defect of primary hemostasis due to:
- Insufficient platelet numbers - should check platelet count first whenever possible.
- Platelet function defect .
- Vascular abnormalities, eg vasculitis.
- Insufficient platelet numbers
Sources
Publications
Refereed papers
- Cowles B E et al (1992) Prolonged bleeding time of Chediak-HIgashi cats corrected by platelet transfusion. Thromb Haemost 67 (6), 708-712.
- Parry B W (1989) Laboratory evaluation of hemorrhagic coagulopathies in small animal practice. Vet Clin North Am Small Anim Pract 19 (4), 729-742.
