Kinetics of postbiopsy levels of serum free prostate-specific antigen and percent free prostate-specific antigen.

Objectives: We evaluated the effects of transrectal ultrasound-guided biopsy of the prostate on serum total and free prostate-specific antigen (PSA) and the free/total PSA ratio and factors affecting variations in PSA levels.

Methods: Serum total and free PSA levels and the free/total PSA ratio were determined in 48 men (mean age 66+/-7 years) before and 1 hour, 8 days, and 30 days after prostate biopsy. At least six cores were taken using a biopsy gun with an 18-gauge needle.