PSA: what it is, what it tells you and when it’s tested

PSA, prostate-specific antigen, is a protein made by the prostate. It keeps semen fluid, and a small amount passes into the blood. It rises when the prostate grows, is inflamed or infected, and also with cancer. That is why a high PSA is not a diagnosis.

When it’s tested

Doctors order it if you have trouble passing urine, to follow men already treated for prostate cancer, and as an early detection check in men without symptoms.

For early detection, the European urology guidelines say to talk it through with your doctor from 50, from 45 if prostate cancer before 60 runs in your family or you are of African descent, and from 40 if you carry a BRCA2 mutation. The European Union asks countries to pilot organised programmes, with PSA followed by an MRI scan. In Italy, Lombardy has started a free regional programme.

Screening has pros and cons: it can find a serious cancer early, but also slow cancers that would never have caused harm. That is why it is a choice to make with your doctor, and Rosa does not include it. Rosa does include a urine test, which can show an infection, one of the causes of a high PSA.

What it tells you, and what it does not

A high PSA says the prostate is releasing more protein than usual. Most often it is an enlarged or inflamed prostate. Sometimes it is cancer.

A normal PSA does not rule out cancer, and a high PSA does not confirm it. How it changes over time matters a lot.

If it is high, the next step is usually not a biopsy: the PSA is repeated and, if needed, an MRI scan is done. A urologist decides on a biopsy, usually based on the scan.

That is why it is read together with other tests:

Normal PSA levels

The lab decides what is normal. Many lab reports give a total PSA up to 4 ng/mL.

PSA rises with age, because the prostate grows. So some labs use limits by age: up to 2.5 from 40 to 49, 3.5 from 50 to 59, 4.5 from 60 to 69 and 6.5 from 70 to 79.

If you take finasteride or dutasteride for your prostate or your hair, PSA falls by about half. Tell your doctor, because the value has to be read differently.

What your result means

Find the row for your result, in ng/mL. Your age, your family history and how it changes over time count too.

If your PSA is high or low

What can skew the result

A few things raise PSA for a while, without any cancer. It helps to know them before your blood test.

When to worry

Talk to your doctor if:

Frequently asked questions

What are normal PSA levels by age? Many lab reports give up to 4 ng/mL. Some labs use limits by age: up to 2.5 from 40 to 49, 3.5 from 50 to 59, 4.5 from 60 to 69 and 6.5 from 70 to 79.

Does a high PSA mean cancer? No. More often it is an enlarged prostate, inflammation or an infection. Your doctor repeats the test and, if needed, asks for an MRI scan.

At what age should I have a PSA test? The European urology guidelines say to talk it through with your doctor from 50, from 45 if it runs in your family, from 40 if you carry a BRCA2 mutation.

How often should PSA be repeated? It depends on the result and your risk. With a low PSA and no family history, you can wait several years. Decide with your doctor.

What should I avoid before a PSA test? Sex or ejaculation in the two days before, and long bike rides. If you have a urine infection, wait until it has cleared.

Does Rosa test PSA? No. Prostate screening is a choice to make with your doctor. Rosa includes a urine test and creatinine, together with the other 80+ biomarkers.

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