Comparison of total prostate-specific antigen and derivative levels in a screening population of black, white, and Korean-American men.

Numerous studies have assessed serum total PSA (tPSA) levels among different races. We extended the serum biomarker profiling using prostate-specific antigen (PSA) derivatives in age-matched screening populations that included white, black, and Korean-American patients. The median ages were 61 years for white and black patients and 63 years for Korean-American patients. Serum samples from 70 men in each ethnic group were analyzed using 3 different tPSA assays (Tosoh AIA 600II, Bayer Immuno-1, Roche Elecsys 2010). The percentage of free PSA (fPSA) was measured directly by Roche Elecsys 2010 immunoassay and then calculated from complexed PSA (cPSA) and tPSA results determined with the Bayer Immuno-1. The percentage of cPSA was determined using cPSA and tPSA assayed by the Immuno-1 method. Statistical analyses included nonparametric Kruskal-Wallis and analysis of variance (ANOVA) evaluations. There were no differences noted in the tPSA values based on ANOVA among the 3 races irrespective of the assay platform methodology employed. Also, the PSA derivatives, percentages of fPSA and cPSA, evaluated using the Kruskal-Wallis test, showed no significant differences for either derivative assayed on 2 different assay platforms among the 3 groups. In a contemporary screening population comparing tPSA, percentage of fPSA, and percentage of cPSA levels in 3 races, there were no significant differences identified among the groups.