Fviii inhibitor assay

A method of testing for FVIII inhibitors in a patient sample, the method comprising the following steps:

• a. providing a previously obtained patient plasma sample,
• b. providing a buffered normal pool plasma sample,
• c. providing a control plasma sample which is clotting factor VIII (FVIII)/von Willebrand Factor (VWF) deficient,
• d. heat treating the samples provided in steps a) to c),
• e. adding recombinant FVIII (rFVIII) to the control plasma sample,
• f. combining the patient plasma sample and the control plasma sample with rFVIII to obtain a test mixture,
• g. combining the normal pool plasma sample and the control plasma sample with rFVIII to obtain a control mixture,
• h. incubating the test mixture and the control mixture for less than 30 minutes, and
• i. analyzing the mixtures for residual rFVIII activity in the absence of VWF.