Prostate Specific Antigen [PSA] PSA is a tumor marker that can be used to screen for prostate cancer. The incidence of prostate diseases increases year by year with age, and the development of prostate tumors is no exception. Regular monitoring of TPSA and free PSA and their ratios for early screening of prostate cancer by comprehensive physician examinations is indicated for men over 40 years of age. ①Total PSA (t-PSA) in serum includes two types: the lesser one is free PSA (f-PSA) with a half-life of 0.75 to 1.2 hours; the large amount exists as compound PSA (c-PSA) with a half-life of 2 to 3 days; ②PSA is highly specific for prostate cancer, with an overall positive rate of 82% to 97%; ③The ratio of f-PSA and t-PSA has important diagnostic value. The higher the PSA concentration, the smaller the f-PSA/t-PSA ratio, the greater the likelihood of prostate cancer. The higher the PSA concentration, the smaller the f-PSA/t-PSA ratio, the greater the likelihood of prostate cancer. The f-PSA/t-PSA ratio is commonly used clinically to identify benign and malignant prostate tumors. It is not meaningful to check the prostate ultrasound and color ultrasound during physical examination to determine whether there is a tumor or not. You should first check the PSA, and if there is an abnormality, further check the prostate MR, preferably with prostate DWI, and then according to the specialist’s guidance whether a puncture biopsy is needed???