Prostate-specific antigen of 5.5 ng/ml is usually not important, but further active examination is recommended to exclude the possibility of prostate cancer. The normal reference value of prostate-specific antigen ranges from 0 to 4.0 ng/ml, and its elevation can be caused by prostate hyperplasia, prostatitis, prostate cancer and other factors. 1. Prostatic hyperplasia: mild elevation of prostate specific antigen may be caused by prostatic hyperplasia, at this time, generally does not matter, the patient can choose to further prostate MRI, puncture biopsy to clarify whether there is a prostate tumor. 2. Prostatitis: patients with mildly elevated prostate-specific antigen, such as patients with urinary frequency, urinary urgency, urinary pain, fever and other symptoms, suggesting that there may be prostatitis, should be actively treating prostatitis, to be stabilized and then re-examined prostate-specific antigen. 3. Prostate cancer: prostate cancer patients usually lead to elevated prostate-specific antigen, patients with prostate-specific antigen 5.5 ng/ml, suggesting that there may be prostate cancer, it is recommended to carry out prostate magnetic examination, prostate aspiration biopsy and so on. 4. Other: such as catheterization, rectal diagnosis, prostate puncture, prostate massage, etc. may lead to elevated prostate specific antigen. It is recommended to review the test in time. Higher prostate specific antigen suggests that the patient should be further examined to find out the cause.