A 5-year-old boy has his blood drawn for platelet aggregation studies. Ristocetin aggregation (RIPA) comes back abnormal with all other agonists displaying normal aggregation. VWF antigen is within normal limits. What is the most likely reason for this discrepancy?

Question

Quizplus · Accepted Answer

Abnormal RIPA with normal VWF antigen levels suggest a qualitative defect of platelet function. Multimer analysis may be done to confirm the diagnosis but a qualitative platelet disorder remains the most likely explanation. The VWF antigen test is not likely to be the issue as it was within normal limits. RIPA exam can be done again but is unlikely to change the result.

A 5-Year-Old Boy Has His Blood Drawn for Platelet Aggregation