Prostate Specific Antigen (PSA)

Prostate specific antigen (PSA) is a protein made by the prostate gland, a small gland below the bladder in people with male reproductive anatomy. Small amounts of PSA leak into the bloodstream, where they can be measured by a blood test.

PSA cannot be used by itself to diagnose prostate cancer. Many other conditions, as well as ordinary activities and medicines, can also cause PSA levels to rise, which means a raised PSA is not the same as a diagnosis of cancer.

PSA also tends to rise with age, partly because the prostate gland typically enlarges as men get older, and a larger gland will release more PSA into the blood even without any disease.

Australia has no organised, population-based screening programme for prostate cancer. PSA testing happens one person at a time, as a shared decision between you and your GP, not as a blanket recommendation.

In May 2026 the National Health and Medical Research Council (NHMRC) approved the recommendations of the 2026 Guidelines for the Early Detection of Prostate Cancer in Australia, which supersede the 2016 guidelines. They advise GPs to start a conversation with men aged 50 and over about risk factors for prostate cancer and the possible benefits and harms of testing. For men aged 45 to 49, GPs are advised to work out whether the man is at higher risk and, if he is, to start the same conversation. The guidelines are recent, and some guidance GPs use, including the RACGP's preventive health guidelines, still set out the earlier approach when this page was last reviewed, so what your GP suggests may differ in detail. The guidelines call an informed discussion, with shared decision making and patient choice, key to good clinical practice.

The guidelines also set out what those benefits and harms are. On the benefit side, they draw on three randomised trials with more than 13 years of follow-up. In a European trial that combined several centres, men were offered a test primarily every four years, starting between ages 55 and 69. After 16 years, about 71 in every 10,000 men offered testing had died of prostate cancer, compared with about 89 in every 10,000 men who were not, a difference of roughly 2 men in every 1,000. In the centre of that trial with the largest effect, whose schedule is similar to the one the guidelines now suggest, men were offered a test every two years starting between ages 50 and 64. After 18 years, about 98 in every 10,000 of them had died of prostate cancer, compared with about 150 in every 10,000 men who were not offered testing, a difference of roughly 5 men in every 1,000. The guidelines also note that trials have not consistently found a benefit. In a second trial, men aged 50 to 69 were offered a single PSA test, and after 15 years the guidelines put the difference at about 6 in every 10,000, which they class as not clinically important and rate as high-certainty evidence. In a third, yearly testing for six years made no clinically important difference after 16 years, although the guidelines rate that evidence as low certainty, because of a high risk that men in the comparison group were also being tested and because a substantial proportion of the men in the trial had probably had a PSA test in the three years before they joined it. The benefit that was found came from regular testing with follow-up over many years, and took six to seven years to first appear.

On the harm side, the guidelines report that PSA testing has led to more diagnoses, particularly of low-risk cancers, and more biopsies, and they list the anxiety and stress caused by a raised result. Some of the cancers found would never have caused symptoms in a man's lifetime, which is called overdiagnosis, and it matters because surgery and radiotherapy carry significant risks to urinary, bowel and sexual function. In an Australian and New Zealand registry cited by the guidelines, 9 to 12% of men treated with surgery or radiotherapy for localised prostate cancer reported, a year after treatment, that urinary function was a moderate or big problem, and 34 to 45% reported the same of sexual function. Those figures are for men who went on to have treatment, not for every man who has a PSA test, and the guidelines count treatment side effects among the possible harms of testing. The guidelines add that the trials reporting the extra diagnoses and biopsies ran before two changes in Australian practice. An MRI scan is now used to decide who needs a biopsy, which they say reduces unnecessary biopsies by approximately 50%, and about 80% of men diagnosed with low-risk prostate cancer in Australia and New Zealand in 2021 were managed with active surveillance (regular monitoring in place of immediate treatment).

Weighing the two, the guidelines' working group judged that for men aged 50 to 69 who are not at higher risk, the benefits of two-yearly testing outweigh the harms in current Australian practice. It had trial evidence for the benefits but only an estimate for the harms, because none of the trials it reviewed measured the harms of testing where MRI and active surveillance are routine. It made the recommendation a conditional one, saying more evidence on men's values and preferences, acceptability and feasibility is needed before it could be a strong one, and the recommendation is due for review by 17 May 2028. The guidelines still leave the decision to each man, after a discussion of the possible benefits and harms with his GP, and note that anyone may opt out, or opt back in, at any time.

For men who then decide to test, the guidelines suggest GPs offer a PSA test every two years between the ages of 50 and 69, and propose the same from age 45 for men at higher risk. The guidelines define higher risk as a risk of clinically significant prostate cancer, or of dying from prostate cancer, that is at least double that of Australian men overall. Their definition includes men with a brother diagnosed with prostate cancer, a father diagnosed before the age of 65, or two or more second-degree relatives (such as uncles or grandfathers) who died of prostate cancer, Black men of sub-Saharan African ancestry, and men with a BRCA2 gene mutation. They also suggest counting a man as higher risk if his father was diagnosed at any age, and propose the same if two or more second-degree relatives were diagnosed. Put simply, a father or brother diagnosed with prostate cancer at any age, or two or more second-degree relatives diagnosed, counts as higher risk under the guidelines. Being at higher risk changes when the guidelines advise GPs to start the conversation, and lowers the PSA level at which they advise a repeat test for men aged 50 to 69. It is not a prediction. The guidelines also note that familial syndromes such as hereditary breast and ovarian cancer and Lynch syndrome are associated with an increased risk, and point GPs to the same higher-risk testing recommendation. Cancer Institute NSW's eviQ guidance for men with a BRCA2 gene mutation differs from these guidelines and recommends yearly PSA testing from age 40, so it is worth raising with your GP or familial cancer service. The same testing recommendations apply to Aboriginal and Torres Strait Islander men.

The guidelines do not propose routine testing for men aged 45 to 49 who are not at higher risk, although a man of that age who is interested in his prostate health may be offered an initial test after the same discussion. If that result is below 1.0 μg/L, the guidelines say no further PSA testing is recommended until age 50. That is advice to GPs about when to test again in men without symptoms, not a finding that the prostate is healthy, and it does not apply to men at higher risk. The guidelines chose 1.0 μg/L because it is typically the 75th percentile for Australian men aged 40 to 49, so about one in four men of that age have a result at or above it, and they cite studies in which men of that age with a PSA at or above the 75th percentile were at higher risk of clinically significant prostate cancer. For men aged 70 and over, the guidelines base the decision on a clinical assessment that takes in life expectancy, other health conditions, and the man's own values and preferences. They suggest offering PSA testing only to men whose life expectancy is greater than seven years, because in the European screening trial this recommendation rests on, a reduction in deaths from prostate cancer first appeared six to seven years after testing began. For men over 70 whose PSA is below 5.5 μg/L, the guidelines say further testing may be discontinued, and that a man who chooses to continue is offered testing after an informed discussion and an individual clinical assessment. Their reasoning is that men over 70 who have had PSA tests before have a very low risk of dying from prostate cancer, particularly when their PSA is below 5.5 μg/L. Stopping is a choice, not a finding that the prostate is healthy. None of the guidelines' approved testing recommendations starts before age 45. The two-yearly recommendation for men aged 50 to 69 is a conditional one. The proposals to offer testing to men aged 45 to 49 and to men aged 70 and over are consensus recommendations, made where the guidelines found no trial evidence to base a protocol on.

These recommendations are written for health professionals working with men who have no history or symptoms of prostate cancer, and the guidelines say they are not intended for the general public, so what they mean for you is a conversation to have with your GP. Changes or problems with urinating are a reason to see your GP, whatever your PSA result. Doctors also use PSA to monitor prostate cancer after it has been diagnosed or treated. That monitoring is a matter for the treating doctor, and the thresholds and intervals on this page do not apply to it. A raised PSA is not a diagnosis and a normal PSA does not rule cancer out, which is worth understanding before deciding.

A level at or above these is not a diagnosis, and a level below them does not rule prostate cancer out. They are the levels at which the 2026 Guidelines for the Early Detection of Prostate Cancer in Australia advise GPs to repeat the test within 1 to 3 months and, if the result is confirmed, to offer or consider referral for further investigation. They apply to men with no history or symptoms of prostate cancer who have chosen to test, the same thresholds apply to Aboriginal and Torres Strait Islander men, and the approved testing recommendations start at age 45. Higher risk is defined above, under why it is tested, and includes a man with a father or brother diagnosed with prostate cancer. A reference interval describes the range of results expected in healthy people, varies between laboratories, and in some laboratories rises with age. The guideline thresholds are fixed for each age band, so a result inside the interval printed on your report can still be at or above a guideline threshold, and the reverse can also happen. Either way it is worth going through with your GP. The guidelines say interpretation must also account for other factors, including medicines called 5-alpha reductase inhibitors, which can lower PSA by up to 50%. Only the 3.0 threshold for men aged 50 to 69 sits in an evidence-based recommendation, which the guidelines grade as conditional. The 1.0, 2.0 and 5.5 thresholds are consensus recommendations, based on expert opinion where the guidelines found too little evidence. The guidelines note that 1.0 μg/L is typically the 75th percentile for Australian men aged 40 to 49, so about one in four men of that age have a result at or above it, and they cite studies in which men of that age at or above the 75th percentile were at higher risk of clinically significant prostate cancer. The guidelines also note that PSA may be artificially lower in transgender women taking gender-affirming hormones, which calls for extra care when reading a result against these levels. The guidelines state PSA in μg/L, which is numerically the same as ng/mL. NHMRC approved these PSA testing recommendations for two years, to 17 May 2028, and they are due for review by then.

Laboratory reference intervals vary and are not the same as these guideline thresholds. Go through your result with your GP.

PSA is influenced by many things beyond prostate cancer, which is one reason the test has to be interpreted carefully.

Age is a consistent driver: the prostate gland typically enlarges with ageing, and a larger gland releases more PSA. Laboratory reference intervals vary, and some rise with age for this reason. The 2026 Australian guidelines instead give fixed PSA levels for each age band and risk group, where the 2016 guidelines used percentiles for age for men under 50. Benign prostatic hyperplasia (BPH, a non-cancerous prostate enlargement that mostly occurs in older men) and prostatitis (prostate inflammation) both raise PSA.

Temporary factors can also shift the result. The guidelines note that PSA levels fluctuate over time, may rise for a short time after sexual activity or a prostate biopsy, and can be raised by a recent urinary tract infection. Australian patient information also lists recent ejaculation, anal sex, prostate surgery, and vigorous exercise such as cycling, and says you may be advised to avoid ejaculation and vigorous exercise during the two days before the blood test. If these apply, your GP may recommend waiting a few weeks before retesting. Australian sources differ on a doctor's physical examination of the prostate (a digital rectal examination). The background text of the 2026 guidelines says it does not affect PSA levels, while Australian pathology guidance lists it among the things that can raise PSA for a short time and advises collecting the blood sample before one. If you had one shortly before your blood test, mention it to your GP when you discuss the result.

Some things lower PSA. The guidelines note that 5-alpha reductase inhibitors, medicines used for benign prostatic hyperplasia and other conditions, can lower PSA levels by up to 50%, and that PSA can read lower with obesity, with low testosterone, and in transgender women taking gender-affirming hormones, for whom the guidelines call for extra care when interpreting PSA. Any medicines you take are worth mentioning to your GP so the result can be interpreted accurately. Results from different laboratories can also differ, because PSA test methods vary.

Whether to have a PSA test, and what a result means for you, is a conversation best had with your GP before and after testing, not something to navigate on your own. If your PSA is raised, your GP will look at the level, your age, your symptoms, and your family history.

Under the 2026 Australian guidelines, when a result is at or above the threshold for a man's age and risk, GPs are advised to repeat the PSA test within 1 to 3 months, because PSA levels go up and down. If the repeat test confirms the result, the guidelines advise GPs to offer or consider a referral for further investigation, depending on your age and risk. For men who need further investigation, the guidelines recommend an MRI scan of the prostate (multiparametric MRI, or mpMRI) as the next test after referral, to help work out whether a biopsy is needed. The guidelines suggest that a digital rectal examination is not offered as a routine addition to PSA testing in general practice, although it remains part of a specialist's assessment.

Changes or problems with urinating are a reason to see your GP whatever your PSA result, including a normal one.

A raised PSA is not a diagnosis, and a result below the guideline threshold is not an all-clear. This page is general information and is not a substitute for advice from your GP.

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