The PSA test measures the level of prostate-specific antigen in the blood, a protein produced by the prostate gland. Elevated levels may indicate conditions such as prostate cancer, benign prostatic hyperplasia, or prostatitis. It is commonly used as a screening tool for men, especially those over 50 or with a family history of prostate issues. The test involves a simple blood draw and results are usually available within a few days. While the PSA test can help detect potential problems, it is not definitive for cancer, and further testing may be required for an accurate diagnosis.