PSA (Prostate Specific Antigen) Blood Test Kit

Prostate Specific Antigen is a glycoprotein enzyme produced almost exclusively by prostate epithelial cells. Its normal function is to liquefy semen after ejaculation, allowing sperm to swim freely. A small amount of PSA leaks into the bloodstream, and measuring this provides a window into prostate health. PSA exists in two forms in blood: "free" PSA (unbound) and "complexed" PSA (bound to proteins). This test measures total PSA (both forms combined). PSA is organ-specific but NOT cancer-specific—any condition affecting the prostate can elevate PSA. Benign prostatic hyperplasia (BPH), the non-cancerous prostate enlargement affecting most men over 50, commonly elevates PSA because a larger prostate simply produces more PSA. Prostatitis (prostate infection or inflammation) can dramatically elevate PSA, sometimes to levels that would be very concerning for cancer—but which normalise after treatment. Urinary tract infections, urinary retention, recent ejaculation, vigorous exercise (especially cycling), and prostate manipulation (digital rectal exam, biopsy) all temporarily raise PSA. PSA levels also rise naturally with age as the prostate grows. Age-adjusted reference ranges are sometimes used: broadly, PSA below 2.5 ng/mL is generally considered normal for men under 50, below 3.5 ng/mL for men 50-59, below 4.5 ng/mL for men 60-69, and below 6.5 ng/mL for men over 70. However, there's no absolute "safe" cutoff—some men with prostate cancer have PSA below 4 ng/mL (about 15% of cases), while many men with elevated PSA have benign conditions. This is the fundamental limitation of PSA as a screening test. The value of PSA testing lies not just in single measurements but in tracking changes over time. PSA velocity (how quickly PSA rises over months to years) and PSA density (PSA relative to prostate volume on ultrasound) can help distinguish concerning rises from benign causes. A rapidly rising PSA is more worrying than a stable elevated PSA. This is why establishing a baseline PSA and monitoring trends over time is valuable—it's not just the number, but the pattern. If your PSA is elevated, it does NOT mean you have prostate cancer—most men with elevated PSA do not have cancer. Your GP may recommend: repeat testing (PSA can fluctuate, and a single elevated reading should be confirmed), digital rectal examination (feeling the prostate for abnormalities), multiparametric MRI (mpMRI, which can visualise suspicious areas in the prostate), and potentially prostate biopsy if MRI shows concerning lesions. The modern approach using MRI before biopsy has significantly improved the accuracy of prostate cancer diagnosis and reduced unnecessary biopsies. Results outside age-appropriate ranges, or significant changes from previous results, should be discussed with your GP.