Patent ID: 7291479

Claim:
A diagnostic method for determining the von Willebrand factor (VWF)-cleaving activity of ADAMTS-13 in a test medium, the method comprising the following steps: a) incubating art ADAMTS-13-free VWF with urea to form urea treated VWF, b) providing a test medium comprising unquantified ADAMTS-13, c) adding from 0.5 to 5 U per ml of said ADAMTS-13-free, urea treated von Willebrand factor to the test medium to form a reaction medium, d) incubating the reaction medium, e) adding platelets to the incubated reaction medium, and f) quantifying the ADAMTS-13 activity based on the reduction in the VWF-mediated aggregation of the added platelets in the incubated reaction medium.