[Percent free prostate-specific antigen: a marker for detection of prostate cancer]

We reviewed the use of percent free prostate specific antigen(PSA) to aid in the differentiation of benign and malignant prostate diseases. Percent free PSA may increase the sensitivity and specificity of PSA testing. There is evidence to suggest a benefit cost advantage to a tailored biopsy approach based on percent free PSA. However, differences in study designs and subject populations may account for the confusion in the current literature. Therefore, statistically valid multicenter clinical trials that take into account influencing factors are needed to set assay specific cut points and probability determinations.