PSAtesting

PSA testing, or prostate-specific antigen testing, is a blood test used to measure the concentration of PSA, a protein produced by prostate tissue, in the bloodstream. The test is commonly employed in two main contexts: screening for prostate cancer in asymptomatic men and monitoring for recurrence or progression after treatment for known prostate cancer. PSA levels can be influenced by several factors besides cancer, including benign prostatic hyperplasia, prostatitis, urinary tract infection, recent ejaculation, and recent prostate manipulation.

The testing procedure involves drawing a blood sample and measuring PSA concentration, typically reported in nanograms per milliliter (ng/mL). Clinicians interpret results in the context of age, family history, and other risk factors. A single PSA value is not diagnostic of cancer; elevated levels may prompt further evaluation, such as a digital rectal exam and possibly a prostate biopsy. Several refinements to interpretation exist, including free PSA (the fraction not bound to proteins) versus total PSA, PSA density (PSA divided by prostate volume), and PSA velocity (the rate of change over time). These adjuncts can help distinguish cancer from benign conditions and guide biopsy decisions.

Guidelines on PSA screening vary by country and organization and emphasize shared decision-making due to trade-offs between potential benefits and harms, such as overdiagnosis and overtreatment. Common considerations include age, overall health, and estimated life expectancy. PSA testing remains a tool for risk assessment and disease monitoring, not a definitive test for cancer, and results should be interpreted within a comprehensive clinical context.