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An Unexpected VWD by Lab Diagnosis

I learned about an interesting case at the University of Alabama at Birmingham(UAB) Hospital special coagulation lab today from specialty techs Patti Tichenor andLaura Taylor. A specimen arrived with an order for lupus anticoagulant profile and anti-cardiolipin antibody. The PTT was prolonged and corrected on initial mix.

The UAB protocol recommends a two-hour incubation and repeat mixing study on the incubated sample to detect a specific inhibitor, which usually turns out to be an anti-factor VIII antibody. Whether the result of the incubated mixing study is corrected, indicating a coagulation factor deficiency, or uncorrected, indicating a possible inhibitor, Patti and Laura typically go on to run a factor VIII assay during the incubation, reasoning they will want to do so in either event. It turns out the factor VIII activity was 38%, so they next ordered a von Willebrand factor antigen assay, which turns out to be 35%. The ristocetin cofactor results will follow, but a call to the ordering ophthalmologist reveals the patient was experiencing a retinal hemorrhage. Their appropriate and speedy application of the mixing study protocol provided an unexpected diagnosis and led to an appropriate treatment course.

Comments (1)
Bleeding Disorders
Herb Crown
Aug 23, 2012 5:59am

And that my friend is what we do in the coagulation referenc
And that my friend is what we do in the coagulation reference laboratory, why we do it, why we are so good at what we do and why we love our jobs. Congrats to the UAB staff. Herb Crown

PS, make sure the doc gets written orders in the patient chart for your additional testing.

Thank you, Herb, yes it is rewarding for our lab scientists to interpret assay results with physiologic understanding and stop a pathological process by indicating correct therapy. Yes, Patti and Laura made sure the written orders were generated and posted.

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