Cite this page: Parsons JC. Factor VIII inhibitor assay / Bethesda assay. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/coagulationfactorVIIIinhibitorassay.html. Accessed October 25th, 2021.
Definition / general
- Prepare serial dilutions of patient plasma in citrated saline from 1 : 1 to 1 : 160 (or higher)
- Mix each dilution with an equal volume of normal plasma containing a normal amount of coagulation factors, incubate for 2 hours, then perform factor VIII assay
- Titer of inhibitor is dilution that inhibits 50% of factor VIII in assay
- Can use porcine Factor VIII to assess cross-reactivity and assist in therapeutic decisions