Is a PSA Test Reliable?

One of the most common tools used to screen for prostate issues is the PSA test. But just how reliable is it?

Understanding the strengths and limitations of the PSA test can help you make more informed choices about your health.

If you’re unsure about what your PSA levels really mean or whether this test is right for you, we break down everything you need to know, clearly and simply.

What is a PSA test?

A PSA test measures the level of prostate-specific antigen (PSA) in your blood.

PSA is a protein produced by both normal and abnormal prostate tissue. Elevated levels may indicate the presence of prostate-related conditions, including inflammation, benign enlargement, or, in some cases, prostate cancer.

How is the test performed?

The test itself is straightforward – a simple blood sample is taken to check for elevated PSA levels. However, interpreting those results isn’t always so simple. That’s because PSA levels may fluctuate for reasons that have nothing to do with cancer. Ejaculation, a prostate infection, certain medications, or even recent physical activity like cycling may affect results.

How reliable is the PSA test?

The reliability of the PSA test has been widely discussed in the medical community. While it can be a helpful indicator, it isn’t considered definitive.

PSA tests may return false positives, where the PSA level is high, but no cancer is present. They may also produce false negatives, where cancer exists but the PSA level appears normal.

Despite these limitations, the PSA test remains an essential part of many men’s preventive care strategy. When used alongside other diagnostic tools such as digital rectal examinations (DRE), imaging scans, or biopsies – it may contribute valuable insights.

When should you get a PSA test?

The decision to undergo PSA screening depends on your:

Age
Family history
Overall risk factors.

Men over 50 may consider routine screening, while those with a family history of prostate cancer might start discussions with their doctor earlier, sometimes as young as 45.

For men experiencing urinary symptoms such as increased frequency, difficulty starting or stopping, or discomfort it might be appropriate to explore PSA testing sooner. However, not all symptoms automatically point to serious conditions. The key is professional evaluation and personalised care.

What can cause a high PSA level?

PSA levels can be influenced by a range of factors, many of which are benign. Here are a few common reasons:

Benign Prostatic Hyperplasia (BPH): A non-cancerous enlargement of the prostate that’s common with age.
Prostatitis: Inflammation or infection of the prostate may raise PSA levels temporarily.
Recent ejaculation or physical activity: Activities like cycling or ejaculation shortly before the test may elevate PSA levels.
Urinary tract infections: UTIs may cause inflammation and affect PSA readings.

Understanding the broader context of your results is key. That’s why doctors often review trends over time, rather than making decisions based on a single result.

What happens if your PSA is high?

If your PSA is higher than average for your age group, your healthcare provider may suggest repeating the test after a short period to check for consistency. Additional assessments might include a:

Physical examination
MRI imaging
Biopsy (if necessary).

Not every case of raised PSA leads to treatment. In some instances, patients might be advised to follow a programme of active surveillance carefully monitoring the condition without immediate intervention. Others may benefit from targeted treatments, depending on the underlying cause.

The evolving role of PSA in prostate care

The PSA test has been around for decades, but its role is continuously evolving thanks to improved technologies and a deeper understanding of prostate health. Today, PSA testing is often just one part of a broader assessment strategy.

Some advanced clinics now offer multi-parametric MRI scans, genetic profiling, and precision diagnostics that, when combined with PSA results, may improve diagnostic accuracy and reduce unnecessary procedures.

Reliable diagnosis depends on expert evaluation. While PSA is a useful tool, it’s not a standalone answer. When paired with advanced imaging and experienced clinical assessment, however, it may form a critical piece of the puzzle.

More information: What Not To Do Before A PSA Blood Test

Maneesh Ghei

Mr Maneesh Ghei MS MRCSEd MD (UCL) FRCS (Urol) is a highly experienced Consultant Urological Surgeon and founder of Urocare London, with over three decades of practice in both NHS and private settings across the capital. As Lead Cancer Clinician at Whittington Hospital, Archway, he chairs the multidisciplinary urology cancer meeting, overseeing patient care from diagnosis through to the latest minimally invasive treatments. A pioneer in complex endourology and stone disease management, Mr Ghei led the UK’s first randomised, double-blind trial of intradetrusor botulinum toxin for refractory overactive bladder. He holds an MBBS and MS in General Surgery from India, an MD from University College London, and undertook advanced fellowships in stone disease and laparoscopic surgery, culminating in his Fellowship of the Royal College of Surgeons (Urology). Committed to education and research, he supervises doctoral work in focal therapies and cryotherapy for prostate cancer and champions public awareness through annual Movember fundraising.