From the previous section, we learned that PSA is critical to normal male reproductive function. Patients may be confused – they are visiting the doctor for prostate disease and not for infertility, so why do they need to have a blood test for PSA? PSA, as a single test, has a higher predictive rate of positive prostate cancer diagnosis compared to anal examination and transrectal prostate ultrasound, and can also improve the diagnosis of limited prostate cancer and increase the chance of radical prostate cancer treatment. PSA, anal examination and transrectal prostate ultrasound are currently recognized as the best methods for early detection of prostate cancer. The American Urological Association and the American Society of Clinical Oncology recommend that men over the age of 50 should undergo routine annual anal examinations and PSA. For the population of men with a family history of prostate, annual examinations should begin at age 45. In China, a consensus was reached by expert discussion that routine PSA and anal examinations should be performed for men over 50 years of age with lower urinary tract symptoms, and for the male population with a family history of prostate cancer, regular examinations and follow-ups should begin at age 45. PSA should be performed in men with abnormal anal examination, clinical signs (such as bone pain, fracture, etc.) or imaging abnormalities, etc. There are a number of other factors that can affect serum PSA levels. The PSA test should be performed 1 week after prostate massage, 48 hours after cystoscopy, catheterization, and other operations, 24 hours after ejaculation, and 1 month after prostate puncture. PSA testing should be performed without acute prostatitis, urinary retention, or other conditions. It is necessary to remind the readers again that PSA test, like anal examination, its results are not 100%; to determine prostate cancer, an experienced physician will analyze the necessity of puncture biopsy based on the patient’s test results, combined with other medical history and circumstances, in order to diagnose prostate cancer.