Impact of age on complexed PSA levels in men with total PSA levels of up to 20 ng/mL

Objectives. To evaluate the relationship between age and complexed prostate-specific antigen (cPSA) in healthy white men with no evidence of prostatic disease and total PSA (tPSA) levels of 0 to 20 ng/mL. Methods. A total of 10,530 tests for cPSA and tPSA in men between 40 and 79 years old were performed at Innsbruck University, Austria, between 2001 and 2002. After excluding 263 patients because of follow-up biopsy findings indicating prostatic disease, 10,267 PSA tests were available for study. All serum samples were analyzed using the Bayer Immuno 1 cPSA and tPSA assays. cPSA and tPSA values were determined in subjects with tPSA levels between 0 and 20 ng/mL. The concentrations were calculated for the 50th, 90th, and 95th percentiles of four age groups (40 to 49, 50 to 59, 60 to 69, and 70 to 79 years). For statistical analysis, the Kruskal-Wallis test was used. The 95th percentile was defined as the upper limit of normal. Results. A total of 10,267 PSA tests were available for study. cPSA and tPSA levels correlated linearly and positively with age (P <0.001). Percent free PSA showed a significant increase with age (P <0.001), which may be attributed to the increase in prostate volume with advancing age. Conclusions. Both cPSA and tPSA levels were found to increase with age. The low tPSA and cPSA levels observed at the 95th percentile in men aged 40 to 59 years suggest that lower cutoff values should be used in place of the currently accepted tPSA level of 4 ng/mL. Lower cutoff values may help improve the detection of prostate cancer among otherwise healthy men. (C) 2003 Elsevier Inc.