PSA, short for Prostate-Specific Antigen, is an abbreviation for a single-chain glycoprotein composed of various amino acids. It is secreted by the prostate glandular and ductal epithelial cells and exhibits specificity to prostate tissue. So, what is the normal range for free PSA?

The normal range for free PSA is generally considered to be below 4.0 ng/ml in serum. PSA levels exceeding 10 ng/ml increase the risk of developing prostate cancer. It is usually recommended to simultaneously measure both free PSA and total PSA as part of routine testing. When the serum total PSA value falls between 4-10 ng/ml, the level of free PSA should be considered. In such cases, the level of free PSA shows an inverse correlation with the occurrence of prostate cancer.

Serum PSA serves as a specific marker for prostate cancer and is highly significant in the diagnosis of asymptomatic early-stage prostate cancer. It can be used for prostate cancer screening and early detection. PSA is typically a serine protease produced by prostate epithelial cells and is a glycoprotein that is directly secreted into the prostatic ductal system. Its normal function involves liquefaction of semen clots and is associated with male fertility.

In general, a free PSA to total PSA ratio greater than 0.16 is recommended as a normal reference value domestically. To be more specific, when the ratio of free PSA to total PSA is less than 0.1, the likelihood of developing prostate cancer is over 50%. When the ratio is greater than 0.25, the probability of developing prostate cancer does not exceed 10%. We hope this article can be helpful to you. Wishing you a happy and healthy life.