PSA (Prostate-Specific Antigen)

What exactly is PSA?

PSA stands for Prostate-Specific Antigen. It is a protein with enzymatic properties that is produced exclusively by the prostate. Normally, PSA ends up in the seminal fluid, where it causes the dilution of the semen after ejaculation. This plays a role in sperm motility.

A small portion of the produced PSA leaks directly into the bloodstream via the prostate cells. As a result, PSA is also detectable in the blood, even in completely healthy men. It is precisely this property that makes it possible to measure PSA via a blood test and use it as an indicator of prostate health.

The PSA test was introduced into clinical practice in the late 1980s and has since been one of the most widely used laboratory tests for the assessment of prostate conditions.

What is PSA measured for?

Doctors use the PSA test to assess prostate health. The test is used both for men with symptoms and for men who want preventive insight into their risk profile. An elevated PSA value signals that further investigation may be worthwhile, but does not in itself constitute a definitive diagnosis. Because PSA increases with age, doctors use age-specific thresholds. This is because the prostate typically enlarges as a man gets older, and a larger prostate produces more PSA. Based on Dutch and Scandinavian guidelines, the following threshold values ​​are used as a guideline:

• 3 micrograms per liter (µg/L) for men younger than 70 years
• 5 micrograms per liter (µg/L) for men between 70 and 80 years
• 7 micrograms per liter (µg/L) for men older than 80 years

If the PSA value is above the threshold corresponding to the age, a doctor may decide to perform further diagnostics, such as a referral to a urologist or imaging studies.

What do abnormal values ​​mean?

An elevated PSA level does not automatically mean that prostate cancer is present. Various benign conditions can also increase the PSA value. This is an important fact, as it helps prevent unnecessary anxiety.

Causes of an elevated PSA can be:

• Benign prostate enlargement (benign prostatic hyperplasia, BPH)
• Prostatitis, an inflammation of the prostate
• A urinary tract infection
• Prostate cancer
• Physiological prostate growth due to aging

In prostate cancer, the tumor can disrupt the prostate tissue, causing more PSA to enter the bloodstream than normal. At the same time, benign conditions can lead to similarly high values. Therefore, the doctor always weighs the PSA result in conjunction with symptoms, family history, previously measured PSA values, and other risk factors.

When a slightly elevated value is found without a clear cause, the measurement is sometimes repeated after a few months. In this way, it can be assessed whether the value remains stable or continues to rise. If there is a strong suspicion of prostate cancer, further investigation may follow, such as an MRI scan of the prostate or a biopsy.

Symptoms and when to get tested

In the early stages, prostate cancer often progresses without clear symptoms. When symptoms do occur, they usually involve changes in urination. Examples include a more frequent urge to urinate, difficulty starting the stream, a weak urine stream, or blood in the urine. It is important to know that these symptoms can also be caused by benign prostate enlargement, which is very common in men over sixty.

A PSA test is useful for men with such urinary complaints, but also for men without symptoms who want to consciously monitor their prostate health. Especially in cases of a family history, meaning if a father or brother has had prostate cancer, early testing is a sensible choice.

The result of a PSA test never stands alone. A proper interpretation always requires context: the man's age, his symptom pattern, any medication, and previous measurements. Therefore, always discuss the results with a doctor so that the correct conclusions can be drawn and any necessary follow-up investigations can be initiated in a timely manner.