SERUM LEVELS OF TOTAL AND FREE PROSTATE-SPECIFIC ANTIGEN IN MEN ON HEMODIALYSIS

Purpose: The measurement of prostate specific antigen (PSA) is widely used in screening programs for early detection of prostate cancer. It has been recently shown that the ratio of free-to-total PSA in serum i s lower in malignant than in nonmalignant prostatic disorders and, the refore, might be a parameter to improve screening specificity. We dete rmine the influence of renal failure on serum levels of total and free PSA, and free-to-total PSA ratio. Materials and Methods: Serum concen trations of total and free PSA, and free-to-total PSA ratio were measu red in 93 men undergoing hemodialysis. The control group consisted of 2,298 healthy blood donors. Results: Serum levels of total PSA were no t significantly different between control and hemodialysis patients. S erum free PSA and free-to-total PSA ratio of hemodialysis patients wer e significantly higher than those of controls (p <0.01 to 0.001). Howe ver, these values did not change in uremic patients after hemodialysis . Although serum total and free PSA levels increased with each decade of age, they did not correlate with age in hemodialysis patients. Conc lusions: Serum free PSA as well as total PSA is not eliminated by hemo dialysis, and elevated levels of free PSA and free-to-total PSA ratio in hemodialysis patients may be caused by a concomitant decrease in bi nding proteins. The reference ranges for total and free PSA, and free- to-total PSA ratio may not be necessarily beneficial in hemodialysis p atients.