Free prostate-specific antigen less than 0.88ng/ml is considered normal, but it should be combined with total prostate-specific antigen. Prostate-specific antigen is mainly used for prostate cancer screening and is divided into total prostate-specific antigen and free prostate-specific antigen. When the total prostate-specific antigen is less than 4ng/ml and the free prostate-specific antigen is less than 0.88ng/ml, it is within the normal range, and the possibility of prostate malignancy is generally not considered. When the total prostate-specific antigen is between 4~10ng/ml, not only the free prostate-specific antigen test value, but also need to calculate the ratio between the two, when the free prostate-specific antigen/total prostate-specific antigen is more than 0.16, generally do not consider the possibility of prostate cancer; when the ratio is less than 0.16, need to be further examined, such as prostate puncture biopsy, etc., to diagnose the presence of prostate cancer. When the total prostate-specific antigen is greater than 10ng/ml, then no matter what the free prostate-specific antigen is, it represents an abnormality and further examination is needed to determine the cause. To sum up, if the result of free prostate specific antigen is found to be abnormal, please consult a specialist in a regular hospital.