What is PSA and why should I get it? PSA is a protein produced by prostate cells that can be secreted into the blood serum. For cancer screening, PSA <4ng is its normal value. It is important to emphasize here that it is not true that anything above 4ng is malignant or that anything below 4ng is not malignant. The correct understanding should be that the probability of prostate cancer below 4ng is very low, and the probability of prostate cancer increases gradually if it exceeds 4ng, and the probability is increasing as the PSA value increases. The clinical term for the range between 4 and 10 is the gray zone. The concept of the gray zone is that there are some patients who may have a diagnosis of prostate cancer, but most are not prostate cancer. If the PSA is elevated, should I have a puncture to rule out prostate cancer? The need for a puncture is not based on the PSA alone; there are many ancillary indicators besides the PSA, including free PSA, PSA doubling time, PSA density, prostate tumor volume comparison, etc., all of which can provide the doctor with additional information. After all, in 4-10ng if no puncture is done, there is a possibility that the diagnosis will be missed, but 70% of the puncture results in this group of patients are negative, so it is important to analyze these factors together to be able to try to avoid unnecessary punctures, while not missing patients who should have a puncture. Who should get a PSA test? Almost all patients with prostate cancer are around 45-60 years old. Men usually have PSA screening once a year or once every two years starting at age 45, which can help detect early prostate cancer. In addition, prostate cancer is a very slow progressing disease and screening after the age of 75 is not life-threatening for men with patients who have no previous PSA problems. a single increase in PSA value does not indicate a problem and must be repeated.