PSA - Prostate Specific Antigen (clinical analyzes)



The PSA (Prostate Specific Antigen) test (or assay) is prescribed to men to detect the first signs of an enlarged prostate (gland in the male genital tract whose main function is the production of seminal fluid) and indicate the presence of possible diseases of the gland such as, for example, cancer.

PSA is a protein present in minimal quantities in the blood and is normally produced by the prostate cells where it is most contained.

The examination should be performed annually by men between the ages of 50 and 70, even in the absence of disorders (symptoms). In individuals aged 40 and over, it is usually prescribed if there are cases of prostate cancer in the family.

In fact, among the youngest, the disease is very rare.

In any case, it is always a good idea to contact the treating doctor who, based on an assessment of the general health conditions and family health history, will advise on a case-by-case PSA test and possible use of a specialist visit.

The test

The analysis to perform the PSA dosage (PSA test) consists of a simple blood sample to measure the amount of prostate antigen present in the serum and does not require fasting.

In order to reduce the risk that the test results may be inaccurate, it is important not to take the blood sample if you have a "urinary infection in progress.

Furthermore, in the 48 hours preceding the exam, you should not engage in intense physical activity or have sexual intercourse because PSA levels in the blood could rise.

The values ​​may also increase following a medical examination with internal rectal examination (rectal exploration), performed in the week preceding the test, or after diagnostic tests of the prostate (biopsy type) carried out in the last six weeks.

On the contrary, the use of some drugs or herbal products for prostate care could mask altered levels of PSA, so it is always important to report to your doctor if you are taking medicines or herbal products or supplements.

It is also advisable to carry out the test in quality health laboratories or in reliable analysis centers and to always contact the same structure in the event that further and subsequent checks are to be carried out.


Once the test results have been withdrawn, in the event of the presence of an altered PSA value, it is still important not to be alarmed since the increase in its values, fortunately, does not always mean that a tumor is present.

The causes, both physiological and pathological, of the alteration of the PSA dosage could be many: an enlargement (benign prostatic hypertrophy) or inflammation of the prostate (prostatitis), renal failure, recent intense sexual, physical or sporting activity o the use of even very common drugs can, in fact, increase PSA levels. Its values ​​can also vary according to body weight and an incorrect diet (such as, for example, the use of spirits).

The total PSA value generally considered normal is less than 4 nanograms per milliliter of blood (ng / ml), a concentration thousands of times lower than that detectable in semen.

An absolute value of normality, however, is not defined even if results between 2 and 4 ng / ml most likely indicate the absence of a tumor.

There are different ways of measuring PSA: total PSA, free PSA (or "free") and the ratio between free and total PSA (PSA ratio). These are used by the urologist both to obtain indications on the need for further investigations such as prostate biopsy, and to monitor the disease once it has been diagnosed and treated. In particular, in the first case it is useful to measure both the free PSA and the total PSA and their ratio (ratio), while in the second case only the total PSA is generally determined.

With increasing age, and with the natural enlargement of the prostate due to aging, the PSA values ​​tend to increase. The interpretation of the exam results must therefore always be related to the age of the person who performed the test. A PSA value equal to 4 ng / ml can, in fact, be normal if referred to a 70-year-old person but suspect if found in a 50-year-old individual. For younger men, up to 2.5 ng / mL is considered normal.

A single finding of PSA values ​​above the average should not cause particular concern but, in any case, it is advisable to submit it to the evaluation of your own doctor or specialist (urologist) who will be able to read and correctly interpret the results of the examination, advise any other tests (rectal exploration of the prostate, transrectal prostatic ultrasound, biopsy) or prescribe the repetition of the PSA test to help clarify the possible factors causing the alteration of the values.


Mayo Clinic. PSA test (English)

NHS. PSA testing prostate cancer (English)

National Institute of Health (NIH). National Cancer Institute. Prostate-Specific Antigen (PSA) Test (English)

Italian Association of Cancer Patients, Relatives and Friends (AIMaC). The PSA test: get informed, understand, talk about it

Niguarda Hospital. Laboratory tests. Prostate specific antigen (PSA)

In-depth link

Prostate Cancer UK. The PSA test (English)

Italian Association for Cancer Research (AIRC). PSA

Italian Association for Cancer Research (AIRC). The PSA measurement is not a screening test

Italian Association of Cancer Patients, Relatives and Friends (AIMaC). The PSA test: get informed, understand, talk about it

Umberto Veronesi Foundation. Magazine. PSA test: when is it needed?

Humanitas Research Hospital. Prostate specific antigen (PSA)

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