PSA test and the prostate: what the blood test can tell you

Getting up twice a night to pass urine. A friend's recent prostate scare. Or simply turning 50 and wondering whether a PSA test is something you should have. The PSA blood test is one of the most discussed tests in men's health, partly because it is useful and partly because it is easy to misread. This guide explains what it measures, how to prepare, and how to think about the result.

What PSA is

Prostate-specific antigen (PSA) is a protein made by the prostate, a small gland under the bladder that produces part of the fluid in semen. The NHS describes the PSA test as a blood test to help check for prostate conditions such as prostate cancer or an enlarged prostate (NHS, PSA test).

A raised PSA has several possible causes. LML lists benign prostatic enlargement and inflammation of the prostate (prostatitis), as well as cancer. The NHS is explicit: a high PSA does not mean you have cancer.

Total PSA, free PSA and the ratio

PSA circulates in two forms: bound to proteins and free. The Prostate Specific Antigen (Total) test measures both together. Free Prostate Specific Antigen measures the unbound part.

The Prostate Profile measures total PSA, free PSA and the ratio between them. LML explains that comparing the two helps doctors understand the likelihood of prostate cancer. A 2025 study in men with PSA below 4 ng/mL who were being considered for biopsy found that a lower free-to-total ratio was linked to higher rates of clinically significant cancer, and suggested the ratio as an inexpensive extra piece of information (Sii et al., 2025).

The benefits and limits of PSA testing

PSA testing for men without symptoms is debated. A 2018 systematic review in the BMJ, covering five randomised trials and more than 700,000 men, concluded that screening at best leads to a small reduction in deaths from prostate cancer over 10 years, without changing overall mortality (Ilic et al., 2018). The same review estimated that screening also leads to some men having biopsies and treatment that bring side effects.

LML says much the same in plain language: the test helps identify cases of prostate cancer, particularly when men see their PSA rising over time, but sometimes a high level is investigated and no cancer is found, and sometimes cancer is present with a normal PSA. That is why the NHS does not offer routine PSA screening, though men can ask their GP about testing and discuss the benefits and risks first (NHS, PSA test).

How to prepare

Several everyday things can raise PSA temporarily. The NHS advises that for 48 hours before the test you avoid ejaculation, anal sex, vigorous exercise and cycling (NHS, PSA test). LML gives the same 48-hour advice for ejaculation. If you have had a urine infection, the NHS suggests waiting 4 to 6 weeks after it has cleared.

When does testing usually make sense?

LML notes that PSA testing is often recommended for men over 50, or for those with a family history of prostate cancer, and that it is more informative when repeated over time. It also lists symptoms that call for a PSA test and a visit to a doctor:

• frequent urge to urinate, or getting up many times at night;
• blood in urine or semen;
• pain or burning when urinating, or painful ejaculation;
• dribbling of urine;
• frequent pain or stiffness in the lower back, hips, pelvis or upper thighs.

If you have any of these, see your GP rather than relying on a private test alone. As a general guide, men from 50 (or from 45 with a family history) who choose to test often do so once a year, ideally with guidance on what the results mean for them. Talk to a health professional before deciding.

What happens with a raised result

A single raised PSA is usually repeated. If it stays high, a GP may discuss referral for further tests such as an MRI scan or biopsy (NHS, PSA test). A doctor will consider your age, family history and previous PSA results, as LML also recommends.

How collection works

Collection is always arranged through LML, the laboratory BPR Clinic works with. Depending on the test, you can use a home kit, visit an LML collection point (you search by postcode) or book a phlebotomist to come to your home. BPR Clinic does not take samples itself. PSA tests use a venous sample, so an LML collection point or a home phlebotomist is the usual route. LML reports results one day after the sample reaches the laboratory.

If you are unsure which test fits your situation, write to [email protected], use the form on our website or send a message through the app. We will help you choose, and we will always suggest you share the results with your doctor.

Frequently asked questions

Does a high PSA mean I have prostate cancer? No. PSA can rise with an enlarged prostate, inflammation, recent ejaculation or exercise. The NHS states clearly that a high PSA does not mean cancer.

Should I do total PSA or the Prostate Profile? The Prostate Profile adds free PSA and the free-to-total ratio, which can give more context when total PSA is borderline. Your doctor can advise which suits you.

What should I avoid before the test? For 48 hours, avoid ejaculation, vigorous exercise and cycling, as the NHS recommends.

References

1. Ilic D, Djulbegovic M, Jung JH, et al. BMJ. 2018;362:k3519. PMID 30185521
2. Sii S, Papa N, Yiu TW, et al. BJU Int. 2025;135(4):550-556. PMID 39607059
3. PSA test - NHS. nhs.uk
4. Prostate cancer - NHS. nhs.uk