PSA

PSA stands for prostate-specific antigen test. Prostate-specific antigen (PSA) is a protein produced by prostate cells, primarily found in semen, with a small amount also present in the blood. (A blood-epithelial barrier around the prostate ductal system prevents PSA from directly entering the bloodstream, thus maintaining low PSA concentrations in the blood.) When prostate tissue undergoes cancerous changes or is stimulated, it secretes a large amount of PSA. At this time, the blood-epithelial barrier is disrupted, releasing PSA into the bloodstream, leading to elevated PSA levels during blood tests. The higher the malignancy of the cancer and the greater the damage to normal prostate tissue, the higher the serum PSA level. Therefore, measuring serum PSA levels can directly reflect the prostate's condition, making it the most widely used screening indicator for prostate cancer in clinical practice. If PSA levels are very high, doctors may recommend a prostate biopsy to confirm cancer. Indications Routine PSA testing should be performed for men over 50 with lower urinary tract symptoms. For men with a family history of prostate cancer (i.e., brothers or fathers with prostate cancer), regular PSA testing should begin at age 45. PSA testing should be performed for men with abnormal digital rectal examination findings, abnormal imaging, or clinical signs (such as bone pain, fractures, etc.). PSA testing can be used as an indicator to evaluate the biological behavior of prostate cells after prostate cancer treatment (surgery/radiotherapy/hormone therapy). Reference Normal Values The normal range for PSA is 0-4 ng/ml, but as age increases, the prostate itself enlarges, and serum PSA will also rise accordingly. Clinically, PSA normal values often need to be adjusted according to age, referring to the following standards: 40-49 years: 0-2.5 ng/ml 50-59 years: 0-3.5 ng/ml 60-69 years: 0-4.5 ng/ml 70-79 years: 0-6.5 ng/ml Test results are usually available 2-3 hours after blood collection.