The decision to biopsy men meeting certain clinical criteria for possible prostate cancer can present challenges. For more than two-thirds of men with a non-suspicious digital rectal exam (DRE) and a total prostate-specific antigen (PSA) result between 4–10 ng/ml, biopsy results are benign. Biopsies leave patients exposed to such potential complications as bleeding, pain and infection. 

The Prostate Health Index (phi) test uses a combination of three blood tests to produce a "phi score" to aid in determining prostate cancer from benign prostatic conditions in men meeting the above criteria who are at least 50 years old. In the first large-scale multicenter study, researchers evaluated the clinical utilization of the phi test, based on prospective data from 506 men and historical data from 683 men. Physician questionnaires regarding patient management plans pre- and post-test showed that the phi score impacted patient care decisions in 73% of cases. In addition, significantly fewer biopsies were performed.