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

Claim 18:
19. A method of determining the quantity of a prostate antigen in a sample from a subject, wherein the prostate antigen is intact prostate specific antigen (iPSA), the method comprising:
1) performing an immunoassay on the sample using a capture antibody and a tracer antibody comprising a 4D4 antibody to generate a signal for detecting the quantity of the prostate antigen in the sample, 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;

2) performing the immunoassay on a set of prostate antigen standards using the same capture antibody and tracer antibody to generate a set of signals, wherein each intermediate standard of the set of prostate antigen standards is equidistant from standard above and below it on a logarithmic scale, wherein the quantity of the smallest non-zero standard of the set of prostate antigen standards is below the limit of quantification of the immunoassay, and wherein the largest standard of the set of prostate antigen standards is less than or equal to 15 ng/mL iPSA; and
3) comparing the signal obtained in the sample to the set of signals to determine the quantity of prostate antigen in the sample.