[Prostate specific antigen: utilization modalities and interpretation].

The prostate specific antigen test has become one of the most popular blood test. However, its result should be analyzed with caution due to physiologic variability. The PSA test is performed for prostate cancer (PC) screening or for post-treatment PC surveillance. According to the applied treatment (surgery or radiation therapy with or without hormonal therapy), PSA analysis can confirm biochemical control or relapse. New PSA data regarding the evolution of this biomarker during the surveillance (PSA doubling time and PSA velocity) are now important to consider in case of biochemical relapse.