Patent ID: 7883855

Claim:
A method for assessment of concentration of sirolimus or everolimus in a human blood sample comprising: (a) contacting a human blood sample with an extractive reagent composition comprising dimethyl sulfoxide of at least about 50% by volume of the extractive reagent composition, at least one divalent metal salt of zinc, and water to form a test sample extract wherein the final concentration of dimethyl sulfoxide in said test sample extract is at least 33%; (b) combining at least one antibody that binds specifically to sirolimus or everolimus with the test sample extract to form a test mixture; (c) incubating the test mixture under conditions suitable for formation of complexes between the at least one antibody and any sirolimus or everolimus present in the sample; and (d) detecting the presence of said complexes formed to determine the concentration of sirolimus or everolimus in said sample.