Patent ID: 8236518

Claim:
A method for detecting a FVIII protein or a fragment thereof in a sample, comprising: (a) contacting a sample comprising FVIII protein with a low concentration of reducing agent sufficient to release FVIII from a FVIII-binding molecule; (b) contacting the sample of step (a) with a first anti-FVIII antibody which is capable of binding to a FVIII antigen in the presence of the reducing agent such that the FVIII protein or fragment thereof comprising said antigen binds to said antibody and forms a complex therewith; (c) contacting the complex formed in step (b) with a second anti-FVIII antibody which is capable of binding to a FVIII antigen in the presence of the reducing agent, said second antibody being labeled with a detectable marker, to form a complex which includes the first anti-FVIII antibody of step (b), the FVIII protein or fragment thereof comprising said antigen, and the second anti-FVIII antibody; and (d) detecting the second antibody in the complex formed in step (c), thereby detecting the FVIII protein or fragment in the sample.