Effect of digital rectal examination on serum concentration of prostate-specific antigen.

Prostate-specific antigen (PSA) is used for screening and follow-up of patients with prostate cancer. The effect of certain diagnostic procedures on PSA serum levels is not well defined. Therefore, the effect of digital rectal examination (DRE) on PSA serum levels was investigated. No significant difference was observed in PSA values before and after DRE when blood samples were taken 1-3 min after palpation of the prostate. Kinetic studies demonstrated a significant increase in PSA values up to the factor 3.2 in 14 of 19 patients 2-6 h after DRE. In 9 of 14 cases, PSA was within the initial range 24 h after DRE. That means that a urologist is allowed to take blood samples for the determination of PSA at least within 3 min after palpating a suspicious prostate without getting false-positive results.