PSA: what it can and cannot tell you

PSA is one of the most talked about blood tests in men's health, and one of the most misunderstood. It can pick up prostate problems early, but it can also raise alarm when nothing serious is wrong. Knowing what it measures, and what it does not, helps you use it well.

What PSA is

PSA stands for prostate specific antigen. It is a protein made by the prostate, the small gland below the bladder that helps produce semen. A little PSA leaks into the blood in every man. The amount rises when the prostate grows, becomes inflamed or is irritated, and also in prostate cancer.

That is the key point. PSA is specific to the prostate, not to cancer. A raised level tells you something is going on in the prostate. It does not tell you what.

Why LifePrint uses age-specific ranges

The prostate naturally grows with age, so PSA drifts up over the years in healthy men. A single cut-off for all ages would miss problems in younger men and over-flag older men. LifePrint uses the age-specific upper limits published by Oesterling and colleagues in 1993, which are used in European Association of Urology guidance:

• Under 50: up to 2.5 ug/L.
• 50 to 59: up to 3.5 ug/L.
• 60 to 69: up to 4.5 ug/L.
• 70 and over: up to 6.5 ug/L.

If your age is not known, LifePrint uses 4.0 ug/L. A result above 10 ug/L is flagged separately, because at that level the chance of significant disease is higher. PSA is included in the Well Man panel from age 40, and can be added for younger men who have a reason to test.

Why PSA can be raised when there is no cancer

Most men with a mildly raised PSA do not have prostate cancer. Common, harmless reasons for a higher reading include:

• Benign enlargement of the prostate, which is very common after 50.
• Prostate inflammation or a urinary tract infection.
• Ejaculation in the two days before the test.
• Long or hard cycling, which puts pressure on the prostate.
• A recent prostate examination, catheter or procedure on the bladder or prostate.

Some medicines used for an enlarged prostate or for hair loss lower PSA, roughly by half. If you take one of these, tell your doctor, because a normal looking PSA may actually be raised for you.

What a normal PSA does not rule out

A PSA within the range is reassuring, but it is not a guarantee. Some prostate cancers, including a small number of serious ones, produce little PSA. If you have urinary symptoms, blood in your urine or semen, or bone pain, see a doctor whatever your PSA result.

The downside of testing

PSA testing has a real benefit: it can find cancers early, when treatment works best. It also has real costs. A raised PSA can lead to scans and biopsies that turn out to be unnecessary. It can find slow-growing cancers that would never have caused harm in a man's lifetime, and treating those can bring side effects such as problems with bladder control or erections.

This is why guidelines describe PSA testing as a shared decision. You and a doctor weigh your personal risk, your preferences and what you would want to do with the result before you test, not after.

Who may benefit most

• Men with a father or brother who had prostate cancer, especially at a young age.
• Black men, who have a higher risk of prostate cancer and tend to develop it earlier.
• Men with a known inherited gene change linked to prostate or breast cancer in the family.

For these men, starting to track PSA from 40 is often recommended. For others, a baseline in your 40s gives a personal reference point that makes later results easier to interpret. A PSA that is rising steadily over the years can mean more than one result just above the range.

What to do with your result

Your LifePrint report compares your PSA with the limit for your age and tells you how urgently to follow up. If it is raised, the usual next step is a repeat test and a conversation with a registered healthcare practitioner, who may examine you or refer you to a urologist. This is health information, not a diagnosis.