Generally speaking, a free PSA of less than 0.88ng/ml is normal, but it should be combined with the total PSA to make a comprehensive judgment. Prostate Specific Antigen (PSA) is mainly used to screen for prostate cancer and is divided into total PSA and free PSA. total PSA less than 4ng/ml and free PSA less than 0.88ng/ml are considered normal. The possibility of malignant prostate lesions is generally not considered. When the total prostate-specific antigen is between 4 ~ 10 ng/ml, not only the detection value of free prostate-specific antigen but also the ratio of the two should be calculated. When the free prostate-specific antigen/total prostate-specific antigen is greater than 0.16, the possibility of prostate cancer is generally not considered. When the ratio is less than 0.16, further testing, such as a prostate biopsy, is needed to confirm the presence of prostate cancer. When the total prostate-specific antigen is greater than 10 ng/ml, regardless of the amount of free prostate-specific antigen, it implies an abnormality and requires further testing to determine the cause. If the free prostate-specific antigen result is abnormal, consult a specialist at a regular hospital.