Patent ID: 8889370

Claim:
A method of determining an inhibitor of a proteolytically active coagulation factor in a sample, comprising the steps of: a) providing and incubating a reaction mix comprising i. an aliquot of the sample, ii. a defined amount of a proteolytically active coagulation factor, iii. at least one ligand which binds to the active site of the proteolytically active coagulation factor but is not cleaved by the latter at a peptide bond, iv. a first and a second component of a signal-producing system which act together in such a way that a detectable signal is generated when said first and second components of said signal-producing system are brought into close proximity to each other, and wherein the proteolytically active coagulation factor is associated with the first component of the signal-producing system or will be associated therewith during incubation, and wherein the ligand is associated with the second component of the signal-producing system or will be associated therewith during incubation; b) measuring the signal of the signal-producing system, wherein the amplitude of said signal is inversely proportional to the inhibitor concentration in the sample.