From Kathleen Doig, PhD, Professor, Biomedical Laboratory Diagnostics at Michigan State University. George – a question arose in our senior Medical Laboratory Science class today as students were constructing algorithms to investigate some case problems I gave them. Here’s the question: What is the platelet count for patients with thrombosis due to antiphospholipid syndrome (APA)?
George answered that unlike platelet counts in thrombotic thrombocytopenic purpura or in heparin-induced thrombocytopenia with thrombosis, there is no relationship between thrombotic events in antiphospholipid syndrome and the platelet count. APA includes both arterial and venous thrombosis. In arterial thrombosis, such as acute myocardial infarction, though a few platelets are consumed in the white clot, not enough are consumed to affect the platelet count. In venous thrombosis, such as deep venous thrombosis, the platelets are innocent bystanders, so the count doesn’t change.
I didn’t really have any references for my statement, so I’d like to hear from participants who may have a different opinion or have seen APA cases with thrombocytopenia. Meanwhile, thanks to Kathy and her senior students for their challenging question.