Before the blood test for PSA, you should eat a light diet and avoid smoking, alcohol and staying up late. In addition before the test should also pay attention to: 1. It is recommended to abstain from sex for 48h; 2. If the patient has prostatitis, urinary retention and other diseases, the original disease should be actively treated; 3. Try to avoid the patient for catheterization, prostate massage, rectal fingerprinting and other operations; 4. if Finasteride tablets have been taken before the examination, patients need to be examined after stopping the drug for a certain period of time; Serum PSA is the most organ-specific tumor marker for prostate cancer screening and is susceptible to many factors. Before the test, you should ask your doctor about the relevant precautions and the duration of drug suspension to prevent inaccurate test results.