The PSA blood test is a test that measures the level of prostate-specific antigen (PSA) in a man's blood. PSA is a protein produced by cells in the prostate gland, which sits just below the bladder and surrounds the urethra (the tube that carries urine out of the body). While it's primarily associated with prostate cancer, it's important to understand that an elevated PSA level doesn't
always mean cancer. It’s normal for men to have a small amount of PSA in their blood, and this level generally increases with age.
Who can have a PSA test?
Any man can request a PSA test from his GP in the United Kingdom, especially if he is over 50. Some men, however, are considered at higher risk of developing prostate cancer, including:
Men with a family history of prostate cancer (especially first-degree relatives like a father or brother).
Men of African or African-Caribbean descent, as prostate cancer is more common in these groups.
Men over 50 in general, as the risk of prostate cancer increases with age.
If you fall into one of these categories, your GP may discuss the pros and cons of the test with you. Men who are younger but have a strong family history or other factors that raise their risk can also discuss PSA screening with their doctor.
What could affect my PSA level?
A variety of factors—both cancerous and non-cancerous—can affect your PSA reading. Keep these in mind when considering a test, as they can lead to temporary increases or decreases in PSA:
Urinary or prostate infections (for example, prostatitis)
Recent sexual activity or ejaculation
Vigorous exercise, particularly cycling
Recent instrumentation (such as catheterisation)
Certain medications, including 5-alpha-reductase inhibitors (used for benign prostate enlargement)
Age and prostate size (PSA can rise naturally as you get older)
If you are planning a PSA test, your doctor may advise you to avoid ejaculation or intense exercise for 48 hours beforehand to prevent an artificially high reading.
What does the PSA test involve?
Most people find that the PSA test is simple and quick. It involves drawing a small sample of blood from your arm, usually in a clinic or GP’s office.
You might be advised not to ejaculate or do heavy exercise for 48 hours before the test. A healthcare professional will place a tourniquet around your upper arm and use a needle to take a blood sample from a vein.
The sample is then sent to a laboratory to measure the amount of PSA in your bloodstream. You will normally get the results within a few weeks.
Some men feel nervous about needles, but the procedure is usually swift. If you have concerns, let the person taking your blood know so they can help you stay as comfortable as possible.
What will the test results tell me?
Your PSA test result is usually reported in nanograms of PSA per millilitre of blood (ng/ml). While there are guidelines suggesting what might be considered a typical or raised level for certain age groups, the interpretation is not always straightforward.
What is a normal PSA level?
Healthcare professionals often use age-related reference ranges. The table below provides approximate upper limits of normal PSA levels. Note that different clinics may adopt slightly different cut-off points:
Age range (years)
Approximate upper limit of normal PSA (ng/ml)
40-49
2.5
50-59
3.5
60-69
4.5
>70
6.5
If your PSA level is above these ranges, your doctor may suggest repeating the test or conducting further investigations, such as an MRI scan. However, a raised PSA is not an automatic indicator of prostate cancer, and many factors can contribute to elevated levels (as mentioned above). Conversely, some men with prostate cancer have relatively low PSA readings, underlining why PSA alone cannot confirm or rule out cancer.
What happens next?
The next steps depend on your PSA level, your age, your risk factors, and any symptoms you may have.
If your PSA level is within the typical range for your age and you have no symptoms, your doctor may recommend repeating the test in the future (the frequency will depend on your individual circumstances).
If your PSA is slightly elevated, your doctor may recommend repeating the test in a few weeks or months to see if it remains elevated or returns to normal. They may also consider other factors – such as your family history and ethnicity, and perform a digital rectal examination.
If your PSA is moderately or significantly elevated, your doctor will likely refer you to a urologist for further evaluation, typically for an MRI scan. If any suspicious areas are identified, or your PSA is very high, a prostate biopsy may be recommended. This involves taking small samples of tissue from the prostate to be examined under a microscope.
Regular PSA tests
Even if your PSA result is within a typical range, you might still opt for regular re-testing, especially if you have risk factors such as a strong family history or if you start to develop urinary symptoms. Your GP or specialist will guide you on how often to test. This is sometimes called "active surveillance" or "watchful waiting" if you have been diagnosed with a low-risk prostate cancer. A rising PSA level over time may be more concerning than a single elevated result.
Advantages and disadvantages of the PSA
Deciding whether to have a PSA test can be complex. Below are some points to consider, but it is important to speak with a healthcare professional about your specific situation.
Advantages
Early detection: A rising PSA can signal early prostate changes, sometimes before noticeable symptoms appear. Early-stage prostate cancer can be easier to treat.
Monitoring: If you are on active surveillance or have had treatment for prostate cancer, PSA testing is one way to keep track of changes.
Widely available: The PSA test is a simple blood test that is widely available.
Disadvantages
Not definitive: A high PSA does not necessarily mean you have cancer, and normal levels do not guarantee that you are cancer-free. Additional tests are often required (typically in the form of imaging, e.g. MRI).
False alarms: Anxiety and further invasive tests (like biopsies) may result from raised PSA readings caused by benign factors.
Overdiagnosis and overtreatment: Some prostate cancers grow so slowly they might never cause harm. Discovering these can lead to treatments and side effects that might have been avoidable.
Should I have a PSA test?
The decision of whether or not to have a PSA test is a personal one that should be made in consultation with your doctor. Discuss the potential benefits and risks, considering your age, family history, ethnicity, and any other relevant factors. There is no right or wrong answer, and your doctor can help you make an informed decision that's right for you.
If you do decide to have the test and your PSA levels are raised, remember that further assessment is often needed. In many cases, a temporarily high PSA can return to normal with time or after treating an infection. Should a biopsy confirm prostate cancer, you will be able to explore a range of treatment options, including focal therapy (if the disease is localised and suitable for a targeted approach), surgery, radiotherapy, or other modalities based on the stage and grade of your cancer.
What to do if you are worried about prostate cancer
If you have concerns about prostate cancer:
A urologist or oncologist can provide guidance on screening and testing options. Seeking asecond opinion may also offer reassurance.
Support groups and counseling can help manage emotional stress.
Keeping up with new research and advancements can help you make informed decisions.
Frequently Asked Questions
What is a PSA test for prostate cancer?
A PSA test measures prostate-specific antigen levels in the blood to detect prostate abnormalities, including cancer.
Can PSA levels go down with prostate cancer?
Yes, PSA levels can fluctuate. Certain treatments and lifestyle changes can lower PSA levels.
What is normal PSA for age?
PSA levels vary by age. Generally:
40-49 years: Up to 2.5 ng/mL
50-59 years: Up to 3.5 ng/mL
60-69 years: Up to 4.5 ng/mL
70-79 years: Up to 6.5 ng/mL
What are 5 warning signs of prostate cancer PSA levels?
PSA levels themselves don't cause warning signs. PSA is a blood test result. Importantly, early-stage prostate cancer is usually asymptomatic – it has no noticeable symptoms. Relying on symptoms for detection is unreliable.
Symptoms can develop in later stages, but are often due to the cancer's growth, not the PSA level. These may include:
Difficulty urinating
Frequent urination (especially at night)
Blood in urine or semen
Erectile dysfunction (more often a treatment side effect)
Bone pain (if spread)
Urinary retention
These symptoms are more commonly caused by non-cancerous conditions. See a doctor if you have any of these, but don't wait for symptoms – discuss PSA testing and DRE with your doctor for early detection.
What PSA is stage 4 prostate cancer?
There's no single PSA level that defines Stage 4 prostate cancer. While men with Stage 4 often have elevated PSA (sometimes very high), the PSA level alone doesn't determine the stage. Staging requires a complete evaluation, including:
PSA level
Gleason score (from a biopsy)
TNM staging (using imaging scans like MRI, CT, and bone scans) to assess tumour size, lymph node involvement, and metastasis (spread)
Stage 4 means the cancer has spread to lymph nodes beyond the pelvis (N1) or to distant sites (M1), regardless of the specific PSA number. A high PSA and evidence of spread are needed for a Stage 4 diagnosis.
If you’ve got any questions about your prostate cancer diagnosis or want to know more about HIFU or NanoKnife, don’t hesitate to get in touch with our friendly, knowledgeable team.
