PSA is prostate-specific, antigen (PSA), which as a single test has high guiding significance for the screening and diagnosis of prostate cancer. (1) PSA screening timing: The American Urological Association, (AUA), and the American Society of Clinical Oncology, (ASCO) recommend that men over the age of 50 should receive routine DRE and PSA screening annually. For men with a family history of prostate cancer, annual screening should be performed starting at age 45. In Taiwan, China, there is a consensus among experts to implement the US recommendations. In China, a consensus was reached by expert discussion that routine, PSA and, DRE examinations should be performed for men over, 50, years of age with lower urinary tract symptoms, and for the population of men with a family history of prostate cancer, regular examinations and follow-up should begin at, 45, years of age. The PSA test should be performed after 1 week of prostate massage, 48 hours after rectal examination, cystoscopy, catheterization, 24 hours after ejaculation, and 1 month after prostate puncture. Diseases. Special Note: There is also a growing academic consensus that routine PSA screening may cause overtreatment, and therefore, PSA screening is not recommended. (2) Determination of PSA results: The current consensus at home and abroad is that serum total, PSA (tPSA) > 4.0 ng/ml, is abnormal. For the first time, PSA, abnormal patients are recommended to be reexamined. When the tPSA is between 4 and 10 ng/ml, the likelihood of prostate cancer is greater than about 25% (European and American data). The incidence of prostate cancer in the Chinese population is low, and a set of domestic data shows that the positive rate of prostate cancer puncture is 15.9% when the serum total, PSA, is between 4 and 10 ng/ml,. The serum PSA, is affected by factors such as age and prostate size. The age-specific, tPSA, values for each age group of patients with prostate hyperplasia (BPH) in China are: 40-49, years old, 0-1.5ng/ml, 50-59, years old, 0-3.0ng/ml,, 60-69, years old, 0-4.5ng/ml,, 70-79, years old, 0-5.5ng/ml, and, 70-79, years old, 0-5.5ng/ml. This constitutes the gray area for prostate cancer determination, and the following PSA-related variables should be referred to in this gray area. (3) Free, PSA, (free, PSA, fPSA): fPSA and, tPSA, as routine simultaneous tests. Most studies have shown that fPSA is an effective method to improve the detection rate of prostate cancer with, tPSA levels in the gray zone. When serum tPSA is between, 4 and 10 ng/ml,, fPSA levels are negatively correlated with the incidence of prostate cancer. Studies have shown that if a patient’s tPSA is in the above range and fPSA/tPSA is less than 0.1, the likelihood of prostate cancer in that patient is as high as 56%; conversely, if fPSA/tPSA is >0.25, the likelihood of prostate cancer is only 8%. The domestic recommendation, fPSA/tPSA > 0.16, is the normal reference value (or critical value).