A PSA blood test can help assess prostate health, but it cannot diagnose or rule out prostate cancer on its own. This guide explains who may consider testing, what can affect the result and what happens next.
A prostate-specific antigen (PSA) test measures PSA in a blood sample. PSA is a protein made by prostate cells. A higher result can occur with prostate cancer, but it can also be caused by benign prostate enlargement, inflammation, infection and recent activity that temporarily affects the prostate.
A PSA test is a useful starting point, not a diagnosis. Its value comes from informed consent, careful preparation and clinical interpretation alongside age, symptoms, family history, ethnicity, medicines, examination findings and earlier results. A normal result cannot completely exclude prostate cancer, and a raised result does not mean that cancer is present.
The prostate is a gland below the bladder. It produces fluid that forms part of semen. PSA normally enters the bloodstream in small amounts. Blood PSA often rises as the prostate becomes larger with age, and it can rise when prostate tissue is inflamed, infected or disrupted.
Laboratories usually report PSA in nanograms per millilitre (ng/mL), which is numerically equivalent to micrograms per litre (µg/L). The number should never be interpreted without context.
A PSA test can indicate that the prostate needs further assessment. It may contribute to the investigation of prostate cancer, benign prostate enlargement and prostatitis. It usually cannot identify which condition is responsible, show exactly where a problem is or confirm whether cancer is clinically significant.
If a result is concerning, the next step may be a repeat PSA, a prostate examination, urine testing, specialist assessment or magnetic resonance imaging (MRI). A biopsy may be advised after MRI and risk assessment, but NICE advises against deciding on biopsy from the PSA result alone.
You can speak to a GP or qualified clinician about having a PSA test if you have symptoms that could be related to the prostate, concerns about your prostate health, or an increased risk of prostate cancer.
Your risk of prostate cancer increases with age. Risk is also higher in Black men, men whose father or brother has had prostate cancer, particularly if they were diagnosed at a younger age, and men with certain inherited genetic variants.
If you have a strong family history of prostate cancer, a known pathogenic BRCA2 variant, or another factor that may increase your risk, discuss this with a clinician. They can help you decide whether PSA testing is appropriate and when it should be considered.
The UK National Screening Committee recommends targeted PSA screening every two years for men aged 45 to 61 who have a pathogenic BRCA2 variant and a family history of breast, ovarian, pancreatic or prostate cancer. This is a targeted recommendation rather than a population-wide screening programme, and implementation is being developed across the UK.
Urinary symptoms are common and are usually caused by non-cancerous conditions, but they still deserve assessment if they are persistent, troublesome or changing.
The UK does not currently have a population-wide PSA screening programme.
PSA testing can find some prostate cancers earlier, but it can also miss cancer, lead to further investigations after a benign rise in PSA, or identify a slow-growing cancer that would never have caused harm.
For these reasons, men should be able to discuss the potential benefits and limitations of PSA testing and make an informed decision about whether testing is appropriate for them.
Targeted screening is different from population screening. In 2026, the UK National Screening Committee recommended PSA testing every two years for men aged 45–61 who have both a pathogenic BRCA2 variant and a family history of breast, ovarian, pancreatic or prostate cancer.
This recommendation is aimed at a specific higher-risk group rather than all men. The way this recommendation is implemented may differ between the UK nations.
Several short-term factors can temporarily affect your PSA level and make the result harder to interpret. Tell the clinician arranging the test about any symptoms, recent procedures and all prescribed or non-prescribed medicines.
You can usually eat and drink normally before a PSA blood test.
If you need a repeat test, having it under similar conditions and, where possible, using the same laboratory can make results easier to compare.
A healthcare professional takes a small blood sample, usually from a vein in the arm. The sampling itself takes a few minutes. The laboratory reports the PSA concentration to the clinician or service that requested it. Before the sample is taken, ask when the result will be reviewed, how you will receive it and what follow-up is available.
There is no single number that is safe or concerning for every man. Clinicians consider the result against age-related referral thresholds, previous results, prostate size, symptoms, examination findings, infection, medicines and individual risk factors. Different UK nations and local pathways can use different thresholds.
A single result close to a threshold may be repeated after temporary causes have been excluded. A clear rise over time can add information, but PSA velocity is not a stand-alone cancer test. Small changes may reflect ordinary biological or laboratory variation.
Finasteride and dutasteride can reduce PSA, often substantially. Never adjust the number yourself; give the clinician a complete medication history so the result can be interpreted appropriately.
The clinician first checks whether a temporary explanation is likely and whether the result crosses the relevant referral threshold. Depending on the circumstances, they may repeat the test, perform a digital rectal examination, request urine tests, review earlier PSA values or refer to urology. MRI is now generally the first specialist imaging test for suspected localised prostate cancer in the NHS pathway.
Most raised PSA results are not caused by prostate cancer. Cancer Research UK reports that roughly 72–80% of people with a raised PSA do not have prostate cancer. The result still needs structured clinical assessment rather than a conclusion from one blood test.
Seek urgent assessment if you cannot pass urine, have fever or chills with urinary or pelvic symptoms, feel acutely unwell, or have severe pain. Arrange a prompt clinical review for visible blood in urine, persistent blood in semen, unexplained weight loss or persistent bone or back or loin pain. These symptoms have several possible causes; they should not be self-diagnosed.
There is no universal interval. Follow-up depends on age, baseline PSA, risk factors, symptoms, previous results and the clinician’s assessment.
