Posted October 4, 2011, and still looking for an answer:
Here is a recent case from the ASCLS Consumer Forum. A 5-YO female experiences chronic ecchymoses with minimal trauma, CBC results are normal, platelet count 343,000/uL with normal morphology, bleeding time is 4 minutes. PT, PTT, fibrinogen, and thrombin time are normal. Using light transmittance aggregometry, there is no platelet response to 2 uM arachidonic acid, 2 mg collagen, and to ADP at 1 and 10 uM. Platelets also do not respond to 0.8 and 1.2 mg/mL ristocetin. What condition is likely, and what would you do next?