Patent ID: 11921115
Assignee: OPKO DIAGNOSTICS, LLC
Field: Measurement (Instruments)
Classification: CPC G  C | IPC C  G

Claim 9:
10. A method comprising:
performing an immunoassay using a tracer antibody to measure a level of a prostate antigen in a sample, wherein the prostate antigen is intact prostate specific antigen (iPSA) and wherein the tracer antibody comprises a 4D4 antibody, wherein the immunoassay comprises:
contacting iPSA present in the sample with a capture antibody specific for iPSA and nicked PSA, under conditions in which the capture antibody binds at least to iPSA, thereby producing a capture-antibody-iPSA complex;
combining the capture-antibody-iPSA complex with the 4D4 antibody in a buffer having a pH of 6.5 to 7.0 such that the 4D4 antibody specifically binds to the capture-antibody-iPSA complex; and
detecting the capture-antibody-iPSA complex bound to the 4D4 antibody;

performing the same immunoassay to measure the level of the prostate antigen in each titer in a set of prostate antigen standards, wherein the set of prostate antigen standards comprises between 5 and 15 titers containing known levels of the prostate antigen, wherein the level of the prostate antigen in the largest titer in the set is less than or equal to 15 ng/mL iPSA, wherein each intermediate titer of the prostate antigen is equidistant from the titer above and below it on a logarithmic scale, and wherein the quantity of the smallest non-zero titer of the set is below the limit of quantification of the immunoassay; and
determining the level of the prostate antigen in the sample based on the measured levels of the prostate antigen in the set of prostate antigen standards.