[Correct use of prostate-specific antigen in office practice].

Objective: To standardize interpretation and comments of prostate-specific antigen (PSA) assay results by clinical pathology laboratories in office practice.

Material: From September 2004 to May 2006, interpretation and comments of PSA assay results performed by 100 different laboratories were analysed retrospectively.

Results: Nineteen different PSA assay kits were used. The so-called "normal" value for total PSA was less than 4 ng/ml for two-thirds of kits. Determination of the free PSA/total PSA ratio (91 cases) was based on a cut-off value ranging from 10 to 25% and the frequent laboratory comments (89 cases) more often referred to benign prostatic hyperplasia (51 case) than prostate cancer (nine cases).

Conclusion: The marked diversity of PSA assay techniques currently used and the divergent interpretations by various laboratories lead to problems of interpretation for both practitioners and patients.