Dernière mise à jour : août 25, 2026

PSA appears in most health-check packages sold to men over a certain age, which means a great many men receive a raised result having never actually decided to be screened for prostate cancer. They arrive in clinic frightened, holding one number.

That number is not a diagnosis. It is a starting point, and quite often it turns out to mean very little.

Blood sample being taken for a PSA test as part of a routine health check
Most men meet PSA inside a health-check package rather than as a decision they made.

There is no single number that means cancer

A figure of 4 ng/mL is widely used as a cut-off and is worth understanding rather than trusting. An earlier version of this article called it the current standard definition of an elevated PSA, which is tidier than reality.

PSA is made by prostate tissue, not by cancer specifically. Anything that enlarges, inflames or disturbs the prostate raises it.

What raises PSA, in rough order of how often

And one thing that lowers it

Finasteride and dutasteride roughly halve the PSA. If you take either — usually for an enlarged prostate or for hair loss — the number on your report understates your true level and has to be interpreted accordingly. This was mentioned only in passing at the foot of the earlier version, and it belongs here: a man on one of these drugs with a PSA that looks reassuring may not be reassuring at all. Tell whoever orders the test.

Man cycling, an activity that can transiently raise the PSA level
Cycling in the day or two before the test can raise the reading — worth mentioning when you book it.

The first step is usually to repeat it

PSA varies in the same man from week to week, and a proportion of raised results simply come back normal when checked again — particularly where there has been an infection, a catheter or a recent procedure, in which case the repeat is left several weeks.

Alongside the repeat comes a physical examination of the prostate, which gives information the blood test cannot. Nothing irreversible should follow from a single raised reading, and a man who is offered a biopsy on the strength of one number without a repeat is entitled to ask why.

What is used to decide whether a biopsy is needed

MRI scanner used to image the prostate before deciding whether a biopsy is needed
MRI before biopsy is what allows some men to avoid one altogether.

What the MRI figure actually means

The earlier version credited MRI with over 90% cancer detection rate. That is a misreading of what the number describes, and it has been corrected.

The strength of prostate MRI is the reverse of detection: when it shows nothing suspicious, significant cancer is unlikely to be present — reliable enough that a reassuring scan, in the right clinical context, is a legitimate reason not to biopsy at all. That is genuinely valuable, and it is not the same as finding 90% of cancers. MRI misses some, its accuracy depends on the scanner and on who reads it, and a suspicious area still has to be sampled to know what it is.

If a biopsy is needed

The earlier version described transrectal ultrasound-guided biopsy as the definitive diagnostic test. Practice has moved on, and this page now agrees with the rest of the site: the MRI images are fused with live ultrasound so the needle is aimed rather than scattered, and the needle is passed through the skin of the perineum rather than through the rectal wall, which is what makes serious infection uncommon. See MRI-fusion transperineal prostate biopsy, and what to expect afterwards.

Two things are worth knowing before you agree to one. A negative biopsy does not entirely close the question, since it samples part of the gland. And finding cancer does not automatically mean treating it — a proportion of prostate cancers grow slowly enough that monitoring is the right management, and the grade reported by the pathologist drives what follows. If treatment is needed, see the treatment pathway.

And if you have not yet had a PSA test and are deciding whether to, that is its own question — should I have a PSA test. The link on this page previously pointed to an address that no longer exists.

Symptoms that need attention rather than a repeat blood test

In an emergency in Thailand, call 1669.

Frequently Asked Questions About a High PSA

Does a high PSA mean I have prostate cancer?

No. Most raised results have a benign explanation — benign enlargement of the prostate above all, then prostatitis or urinary infection, recent instrumentation, retention, recent ejaculation or vigorous cycling. PSA is made by prostate tissue generally, not by cancer specifically.

Is 4 ng/mL the line between normal and abnormal?

It is a widely used cut-off rather than a boundary between health and disease. Most men above it do not have cancer, some cancers occur below it, and what counts as normal rises with age and with prostate size.

What happens first after a raised result?

Usually the test is repeated, with an examination of the prostate — and left several weeks if there has been an infection, a catheter or a procedure. A proportion of raised readings return to normal on repeat. Nothing irreversible should follow from a single number.

How should I prepare for a PSA test?

Abstain from ejaculation for about 48 hours and avoid vigorous cycling for a couple of days beforehand. Tell your doctor about any recent urinary infection, catheter or urological procedure, and — importantly — if you take finasteride or dutasteride, which roughly halve the reading.

My MRI was clear. Can I skip the biopsy?

Often, yes. A prostate MRI showing nothing suspicious makes significant cancer unlikely, and in the right clinical context following the PSA rather than proceeding to biopsy is a reasonable choice. It is not an absolute guarantee — MRI misses some cancers and its accuracy depends on the scanner and the radiologist — so it is a decision made together rather than an automatic discharge.

Arranging a consultation

Dr. Soarawee Weerasopone sees patients at Hôpital de Bangkok Siège social and at Samitivej Sriracha Hospital in Chonburi on 088-022-1445. Bring every previous PSA result with its date rather than only the latest one — the trend is worth more than the number — along with a list of your medicines.

La télémédecine de Bangkok Hospital est disponible pour les patients qui ne peuvent pas se déplacer en personne, y compris les patients internationaux — organisez-la à l'avance par e-mail auprès du service d'urologie à bhquro@bdms.co.th. Samitivej Sriracha est uniquement en personne. Les demandes concernant les coûts reçoivent une réponse de l'hôpital, et non de ce site web.

Avis de non-responsabilité : This content is written and reviewed by Dr. Soarawee Weerasopone, a board-certified urologist at Bangkok Hospital Headquarters, and is intended for education only. It is not medical advice, diagnosis or a prescription for any individual, and no advice, diagnosis or prescription is given through personal messaging channels or social media. Dr. Soarawee operates no public social media account; any account offering private consultation in his name is fraudulent. In an emergency in Thailand, call 1669.

Rédigé et révisé par des médecins : Dr Soarawee Weerasopone (Dr Pom) — Urologue certifié, siège social de l'hôpital de Bangkok, en pratique urologique depuis 2016. Fellowship : Chirurgie robotique, Chang Gung Memorial Hospital, Taïwan (2019) · Stage d'observation : Endourologie, Hôpital universitaire Juntendo, Tokyo (2022) · Chercheur et observateur clinique, Département d'urologie Scott, Baylor College of Medicine, États-Unis (2025-2026).

3 réponses

  1. Merci doc. La lecture de vos articles est toujours très instructive. Je vous souhaite une excellente journée !

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