Prostate cancer is the most common cancer in UK men. Around 1 in 8 men will be diagnosed with it in their lifetime, according to Prostate Cancer UK. Caught early, the survival rate is excellent — over 95% at 10 years. The PSA test is one of the simplest tools for catching it early.
What is PSA?
PSA stands for Prostate-Specific Antigen — a protein produced by both healthy and abnormal prostate cells. A small amount circulates in your bloodstream all the time. When the prostate is enlarged, inflamed, or contains cancerous cells, the level rises.
A PSA blood test gives you a single number. By itself, it doesn't diagnose anything — but it's a starting point that, combined with age and trend over time, helps spot when something needs further investigation.
Why does it matter?
Early prostate cancer almost always has no symptoms. By the time men develop urinary changes (frequent urination, weak stream, getting up at night), the cancer has often already grown beyond the prostate. PSA testing is currently the most accessible way to catch it before symptoms.
The NHS doesn't routinely offer PSA testing as a screening programme — but men over 50 (or over 45 if Black, or with a family history) can request a PSA test from their GP. Many men choose to test privately so they can establish a baseline earlier and track their own trend.
What do the numbers mean?
PSA is reported in nanograms per millilitre (ng/mL). UK guidelines (age-adjusted):
- Men 40-49: Generally below 2.5 ng/mL
- Men 50-59: Generally below 3.0 ng/mL
- Men 60-69: Generally below 4.0 ng/mL
- Men 70+: Generally below 5.0 ng/mL
A reading above the age-appropriate threshold doesn't mean cancer — it means it's worth a closer look. Causes of raised PSA include benign prostate enlargement (BPH), urinary tract infection, recent ejaculation, vigorous exercise (especially cycling), or prostate examination — all of which can temporarily push it up.
Total PSA vs Free PSA — what's the difference?
PSA exists in two forms in your blood:
- Total PSA — the combined level of all PSA
- Free PSA — the unbound portion
The Free/Total PSA ratio can help differentiate benign causes from cancer. In simple terms: cancer tends to lower the proportion of free PSA. A ratio above 25% suggests benign causes are more likely; below 10% raises concern. This ratio is most useful when Total PSA is in the borderline range (4-10 ng/mL).
Three things you might not know about PSA
1. The trend matters more than a single number
A man whose PSA has been steady at 2.5 for years and suddenly rises to 4.0 may warrant more investigation than a man whose PSA has always been 4.0. PSA velocity — how fast it changes over time — is one of the most useful screening signals. That's why an early baseline (in your 40s) is valuable.
2. Cycling can artificially raise PSA
Long bike rides apply pressure to the prostate and can elevate PSA temporarily by 10-50%. If you're a cyclist, avoid riding for 48 hours before a PSA test. The same applies to vigorous prostate examination, recent ejaculation (last 48 hours), and active urinary tract infection.
3. Most men with raised PSA do not have cancer
Roughly 3 out of 4 men with elevated PSA turn out to have benign prostate enlargement, infection, or another non-cancer cause. Raised PSA is a "look closer" signal — not a diagnosis. Don't panic at a single elevated reading. Retest after 4-6 weeks (avoiding triggers) and see if it persists.
Who should consider testing?
- All men aged 50 and over
- Men aged 45+ with a family history of prostate cancer
- Men aged 45+ of African or Caribbean heritage (higher genetic risk)
- Men of any age with new urinary symptoms or pelvic discomfort
- Anyone wanting to establish a baseline for future trend tracking
How to test your PSA
We offer three PSA testing options:
- Total Prostate Antigen Test — the standard PSA
- Free Prostate Antigen — useful alongside Total PSA for the ratio
- At Home PSA Test — finger-prick collection in the post
For comprehensive prostate health monitoring, our Prostate Profile includes PSA, Free PSA, and the ratio. Results in 3-5 working days as a clear PDF report.
Browse our prostate health panels →
This article is informational. Chxhealth is a biomarker and genetic data provider — we do not diagnose, treat or prescribe. If your results are outside typical ranges, talk to your GP or a healthcare professional about next steps.
