PSA testing: why 'high' doesn't always mean cancer

What PSA is, what it isn't

Prostate-Specific Antigen is a protein produced by cells of the prostate gland. Both healthy prostate cells and cancerous cells produce it. The key word is "prostate-specific" — not "cancer-specific." Any condition that increases prostate cell activity or disrupts the gland's architecture can raise the PSA.

Age-adjusted reference ranges

Single thresholds ("PSA <4 is normal") are outdated. UK NHS and BAUS reference ranges are age-stratified:

• Under 50 — PSA <2.5 ng/mL
• 50–59 — PSA <3.5 ng/mL
• 60–69 — PSA <4.5 ng/mL
• 70 and over — PSA <6.5 ng/mL

A 55-year-old with PSA 3.2 is within range; a 45-year-old with the same number is not. We apply age-adjusted thresholds when interpreting results.

PSA velocity — change over time

The trend is often more informative than a single result. A rise of ≥0.75 ng/mL per year is a flag for further investigation. In younger men, a rise of ≥0.4 ng/mL per year is significant. We recommend repeating PSA at an interval (typically 3–6 months for an equivocal result, annually for surveillance) and looking at the slope rather than the snapshot.

Free PSA percentage

PSA in blood exists as "free" or bound to other proteins. In benign conditions (BPH, prostatitis), the proportion of free PSA tends to be higher; in cancer, it tends to be lower.

• Free PSA >25% — lower probability of cancer.
• Free PSA 10–25% — intermediate.
• Free PSA <10% — higher probability of cancer.

Free PSA is most useful in the PSA "grey zone" of 4–10 ng/mL. We add it to the panel where appropriate.

Causes of falsely-elevated PSA

This is where most over-interpretation happens. Things that raise PSA without cancer being present:

• Benign prostatic hyperplasia (BPH) — by far the commonest. The prostate enlarges with age; more cells, more PSA. Many men over 60 have some BPH-driven elevation.
• Prostatitis — acute or chronic prostate inflammation. Acute prostatitis can raise PSA dramatically.
• Recent ejaculation — within 48 hours. Abstain for 48 hours before the test.
• Recent digital rectal examination (DRE) — within a week.
• Recent urinary tract infection — wait 4–6 weeks after infection clears.
• Recent prostate biopsy or catheterisation — wait 6 weeks.
• Cycling — prolonged saddle pressure can raise PSA transiently.

Standard advice before PSA testing: abstain from ejaculation for 48 hours, avoid heavy cycling for a few days, and do not test within 6 weeks of a UTI or DRE.

When biopsy is appropriate

Current NICE NG131 guidance largely replaces immediate biopsy with multi-parametric MRI (mpMRI) of the prostate as the first investigation in raised PSA. The pathway looks roughly like this:

• PSA above age-adjusted threshold, or PSA velocity raised, or symptoms with PSA in grey zone.
• GP referral via the two-week-wait suspected cancer pathway.
• mpMRI of the prostate — reported on the PI-RADS scale (1–5).
• PI-RADS 1–2 — low suspicion, often no biopsy needed.
• PI-RADS 3–5 — targeted biopsy of suspicious areas, plus systematic sampling.

This MRI-first approach reduces unnecessary biopsies and the over-diagnosis of clinically insignificant cancers.

Active surveillance

Many low-risk prostate cancers — small, low-grade, confined to the prostate — do not require immediate treatment. Active surveillance means careful monitoring (PSA testing, periodic mpMRI, repeat biopsies if indicated) with treatment only if there is evidence of progression. It avoids the side effects of surgery or radiotherapy (incontinence, erectile dysfunction, bowel symptoms) in cancers that may never cause harm in a patient's lifetime.

The PSA controversy

PSA testing is not currently part of a national NHS screening programme. The reason is balance: PSA testing finds some cancers early enough to save lives, but it also drives over-diagnosis and over-treatment of cancers that would never have caused harm. Major trials (ERSPC, PLCO) have given mixed mortality benefit signals. Current UK position is "informed-choice testing" — PSA is available on request via GP or privately, with discussion of the trade-offs first. We have that conversation at consultation.

Family history

Risk is higher if:

• One first-degree relative (father, brother) diagnosed before age 65 — roughly double population risk.
• Two or more first-degree relatives — higher still.
• Black African or Black Caribbean heritage — roughly double population risk.
• BRCA2 mutation carriers — significantly higher risk.

Family history shifts both the threshold for testing and the threshold for further investigation.

Practical guidance

When to consider PSA testing

• Men aged 50–69 considering informed-choice testing.
• Earlier (from age 40–45) with first-degree family history or Black heritage.
• Symptoms — urinary frequency, hesitancy, nocturia, weak stream, perineal pain, blood in semen or urine (the last two warrant urgent assessment regardless of PSA).

What to bring

• Any previous PSA results, with dates.
• Family history details.
• Current medications (some affect PSA).
• Symptoms diary if relevant.

How results integrate with the NHS pathway

If we test privately and the result is concerning, we provide a written report that your GP can act on. The NHS two-week-wait pathway is the route to mpMRI and onward urology assessment. We support that referral with a clear summary letter. The wider private vs NHS testing guide explains how the two systems interlock, and the reading blood test results in plain English guide explains the general approach to results.

Related testing

For broader men's health context, see our women's hormone panels guide as the sister page on cycle-specific testing for women, and the thyroid panel guide for endocrine testing more broadly. Local pages: Manchester, Sale, Altrincham, Stretford and Chorlton. The brand blood tests service page sets out the broader testing menu.

To book PSA testing with a results discussion built in, call 0161 258 6149 or use our booking page.