Summary

PSA – prostate specific antigen – is measured to screen for prostate cancer, and to monitor the response to treatment in people who have prostate cancer. Rises in PSA levels can be caused by many factors and are not always due to prostate cancer. The PSA test cannot specifically test for cancer and can only show changes happening in the prostate. By itself it isn’t enough to definitively confirm or rule out prostate cancer.

Why get tested?

PSA is a protein made by the prostate cells. Its job is to liquefy semen. Small amounts leak into the bloodstream where it can be measured. In most prostate cancer, more PSA gets into the blood than normal. However, other conditions, activity, and medications can also cause PSA levels to rise. 

Two forms of PSA

PSA exists in two forms in the blood: 

1. free (not bound) 
2. complexed (cPSA, bound to other blood proteins).

The most common test is the total PSA which measures the sum of both. When a doctor orders a PSA test, they are referring to a total PSA test.

Free PSA is sometimes ordered when total PSA levels are only slightly raised. This is to try to differentiate between prostate cancer and non-cancerous conditions.

What can cause raised PSA levels?

Raised levels of PSA are associated with prostate cancer, but they are also seen with prostatitis and benign prostatic hyperplasia (BPH). Levels tend to increase in all men as they age. However, age related reference intervals are not used for the diagnosis of prostate cancer.

The Urological Society of Australia and New Zealand Position Statement on PSA Testing* from September 2022 made the following recommendations:

• PSA testing can be offered to men more than 50 years of age with a life expectancy of at least 10 years, 
• PSA testing can be offered to men at an elevated risk of having prostate cancer. These include men more than 45 years of age with a family history of prostate cancer, men of high-risk ethnicities (including Indigenous men) more than 45 years of age and men carrying BRCA2 mutations more than 40 years of age.

_{*Guidelines for PSA testing are currently under review.}

BPH – benign prostatic hyperplasia

Two-thirds of men who see their doctor with high PSA levels have non-cancerous conditions. BPH is a non-cancerous swelling of the prostate that mostly occurs in older men. Because the prostate gland tends to get bigger with age, it can squeeze the urethra and cause problems in passing urine.

Prostatitis

This is inflammation of the prostate usually caused by an infection, most often when bacteria spill into the prostate from the urinary tract. It can be acute – it comes on suddenly for a short time - or chronic which means it is on-going. With this, there are often other symptoms such as discomfort and tenderness. Prostatitis is treated with antibiotics.

Many things can cause temporary rises in PSA levels. This includes anything that disturbs the prostate such as riding a bike or motorbike, vigorous exercise, having a rectal examination, an orgasm within the past 24 hours, or prostate surgery. Some medications are known to raise levels.

Since prostate cancer shares similar symptoms with many other conditions, your doctor may order other tests, such as a urine culture. If a total PSA level is raised, they may order a repeat test a few weeks later to see whether the PSA levels have returned to normal.

Should you be tested?

Prostate cancer is the most commonly diagnosed cancer in men and the second most common cause of death from cancer in Australian men, with indigenous men having a higher rate of prostate cancer mortality. The Position Statement on PSA testing recommend offering testing from the age of 50 years to men who have been informed of the risks and benefits of PSA testing for prostate cancer.

There is a lot of conflicting advice about PSA testing. However, long term data on PSA screening for prostate cancer has shown that there is a survival advantage from PSA testing. So before getting a PSA test, talk to your doctor about the benefits and risks of having this test. Then you can decide if you wish to go ahead or not. 

Having the test

Sample 
Blood

Any preparation?

You may be advised to avoid ejaculation and vigorous physical activity affecting the prostate, such as bicycle riding, during the two days before the blood test. The sample should also be collected before the digital rectal exam and before (or several weeks after) a prostate biopsy.
 

Your results

Reading your test report

Your results will be presented along with those of your other tests on the same form.  You will see separate columns or lines for each of these tests.

For men with an initial PSA test of more than 3 µg/L, your doctor will consider the need for further testing that may including an MRI scan and prostate biopsy*.

_{*Guidelines for PSA testing are currently under review.}

A sudden increase in total PSA levels suggest prostatitis.

Some cancer cells do not produce much PSA, so it is possible to have a normal result yet have cancer. Recent studies have shown that there is still a small risk of prostate cancer, even if blood PSA levels are normal for age.

PSA levels can vary, so your doctor may decide to repeat the test to compare your results over time.

The only definite way to confirm whether prostate cancer is present or not is by prostate biopsies (taking small samples of tissue).

Reference Intervals

Your Pathology Laboratory will report your results compared to reference intervals (sometimes called a normal range). 

• Reference intervals are the range of results expected in healthy people. However, your doctor will advise you on follow up based on your PSA level.
• When compared against them your results may be flagged high if they sit outside this range.
• Many reference intervals vary between labs so only those that are standardised or harmonised across most laboratories are given on this website.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. It depends on your personal situation. Your results need to be interpreted by your doctor.

Follow-up tests

If you have a result higher than the PSA recommended cut-off level, your doctor may arrange for you to have a biopsy. This is a surgical procedure that takes small pieces of tissue from different parts of the prostate.  The samples are sent to the lab where they are processed and looked at under a microscope. A pathologist specialising in tissue investigates the prostate cells for cancer and sends a report to your doctor. They provide information on the type of cancer and whether or not it is aggressive.

If cancer is detected, you may need to have imaging tests such as MRI, CT or bone scans to see if the disease is contained to the prostate or if it has spread, and to help with management and treatment decisions. 

Any more to know?

You may come across the following terms:

• PSA Density – the relationship of the PSA level to the size of the prostate measured by ultrasound examination.
• PSA Velocity – how quickly PSA levels change over time.
• PSA Doubling Time – the time it takes for the PSA value to double. This may be useful in following treatment and determining the type of treatment. 

More information

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

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