Clinical Chemistry, Vol 38, 735-742, Copyright © 1992 by American Association for Clinical Chemistry

Ultrasensitive radioimmunoassay of prostate-specific antigen

HC Graves, N Wehner and TA Stamey
Department of Urology, Stanford University Medical Center, CA 94305- 5118.

We describe a modification of the Yang Pros-check radioimmunoassay for prostate-specific antigen (PSA) that increases the analytical sensitivity of the assay approximately threefold (from a working range of 0.3-50 to 0.1-1.2 micrograms/L). It can detect PSA added to zero- concentration diluent (bovine serum albumin solution) at 0.10 microgram/L or added to zero-concentration control female serum at 0.20 microgram/L (P less than 0.05). In 26 patients tested after cystoprostatectomy for bladder cancer (who had normal prostates without cancer on histologic examination), PSA values by this ultrasensitive assay were all less than 0.10 microgram/L. Therefore, we propose this value as the upper limit of the 95% reference interval. In a retrospective study of two patients who developed recurrent prostate cancer, serum PSA values increased above the 0.1 microgram/L detection limit 175 and 581 days before increasing above the 0.3 microgram/L detection limit of the standard Yang assay. This ultrasensitive radioimmunoassay of PSA should prove more useful than current methods for detecting early recurrence of prostate cancer.

The following articles in journals at HighWire Press have cited this article:

				S.-F. Chen, Y. Xu, and M. P.-C. Ip Electrochemical Enzyme Immunoassay for Serum Prostate-Specific Antigen at Low Concentrations Clin. Chem., August 1, 1997; 43(8): 1459 - 1461. [Full Text]