Prostate-specific antigen (PSA) is also produced by prostate epithelial cells and belongs to the kinase family of proteins, which are present in semen and prostate fluid, and less in serum, where prostate-specific antigen consists mainly of free prostate antigen and complex prostate antigen.
In clinical work the normal value of total prostate antigen<4ng/ml and free/total prostate antigen>0.25 are elevated during operations such as prostate enlargement, prostate inflammation, prostate cancer, prostate injury, indwelling urinary catheter, and prostate massage. The total prostate antigen is at a normal level, but only the free prostate antigen is elevated, there is no significant abnormality, such as total prostate antigen >10ng/ml should be combined with the presence of local surgical operations, the presence of combined acute prostatitis, prostate hyperplasia prompted by the antigen increase factors, in order to be able to exclude the presence of prostate cancer, the above two cases when the free prostate antigen is elevated or not is less significant, such as total prostate antigen >10ng/ml. The more the ratio of free and total prostate antigen, the greater the possibility of malignant disease. The higher the free prostate antigen alone, the more meaningful it must be in combination with the above.