Brief report: Free prostate-specific antigen test utilization. Consistency with guidelines

BACKGROUND: The American Cancer Society and American Urologic Association recommend prostate cancer screening for average-risk men between the ages of 50 and 75 years using digital rectal examination and prostate-specific antigen (PSA) testing. Measuring the percent free PSA may improve test specificity for detecting prostate cancer when the total PSA is between 2.5 and 10 ng/mL. OBJECTIVE: To assess whether free PSA testing practices are consistent with published screening guidelines. DESIGN: Retrospective analysis of free PSA testing performed by a national reference laboratory between October 1, 2003 and September 30, 2004. MEASUREMENTS: Free PSA and total PSA results and the age of the patient at testing. RESULTS: Over 24% of free PSA tests were performed on patients greater than 75 years of age, and 38% were performed on patients with a total PSA either less than 2.5 ng/mL or greater than 10.0 ng/mL. CONCLUSIONS: A substantial proportion of free PSA tests performed in a national reference laboratory appeared to be inconsistent with existing screening guidelines. This raises concern that some of these patients may have received inappropriate diagnostic workup and/or therapy, resulting in excess medical costs and potential harms.