Serum-to-Urinary Prostate Specific Antigen Ratio: Its Impact in Distinguishing Prostate Cancer When Serum Prostate Specific Antigen Level is 4 to 10 ng./ml.

Our results suggest that the serum-to-urinary PSA ratio may be useful in distinguishing BPH from prostate cancer, particularly in the diagnostic gray zone of serum PSA between 4.0 and 10.0 ng./ml.