Your PSA Test, Explained

Your PSA came back and you're staring at one number. Here's what that number actually measures, why it ends up in your blood at all, where the famous 4.0 threshold came from, and what the current AUA/SUO and EAU guidelines say to do about it. I'm a urologist and andrologist. Every figure in this video comes from the guideline text, the original trials, or the standard textbooks, and they're all listed below so you can check them yourself. 1. American Urological Association / SUO. Early Detection of Prostate Cancer: AUA/SUO Guideline (2023; amended 2026). https://www.auanet.org/documents/Guid... 2. Updates to Early Detection of Prostate Cancer: AUA/SUO Guideline (2026). J Urol. DOI: 10.1097/JU.0000000000004995 3. European Association of Urology. EAU Guidelines on Prostate Cancer — Diagnostic Evaluation. https://uroweb.org/guidelines/prostat... 4. Partin AW, Dmochowski RR, Kavoussi LR, Peters CA (eds). Campbell-Walsh-Wein Urology, 13th ed. Elsevier. — Vol. I, Ch. 3 (Laboratory studies / PSA); Vol. I, Ch. 27 (Prostatitis); Vol. II, Ch. 66 (Prostate and seminal vesicles: anatomy). 5. Hall JE, Hall ME. Guyton and Hall Textbook of Medical Physiology, 15th ed., 2026. Elsevier. Ch. 81 (Reproductive and Hormonal Functions of the Male). ISBN 9780443111013. 6. Thompson IM, Pauler DK, Goodman PJ, et al. Prevalence of prostate cancer among men with a PSA level ≤4.0 ng per millilitre. N Engl J Med 2004;350:2239–46. DOI: 10.1056/NEJMoa031918 (PMID 15163773) 7. de Vos II, Roobol MJ, et al.; ERSPC Investigators. European Study of Prostate Cancer Screening — 23-Year Follow-up. N Engl J Med 2025. DOI: 10.1056/NEJMoa2503223 8. Jiandani D, Randhawa A, Brown RE, et al. The effect of bicycling on PSA levels: a systematic review and meta-analysis. Prostate Cancer Prostatic Dis 2015;18:208–12. DOI: 10.1038/pcan.2015.16 9. Mattsson JM, Ravela S, Hekim C, et al. Proteolytic activity of prostate-specific antigen (PSA) towards protein substrates. PLoS One 2014;9(9):e107819. DOI: 10.1371/journal.pone.0107819 Links: Instagram:   / atamas.m.d   Linkedin:   / mikhail-atamas-a35a99244