Positive bowel screening test? What it means and what happens next
A letter saying your bowel screening test is positive can be unsettling. Take a breath: a positive result is common, and most people who get one do not have bowel cancer. But every positive result needs to be followed up properly, and promptly. Here's what it means, and exactly what happens next.
What a “positive” result actually means
The free home kit from the National Bowel Cancer Screening Program is an immunochemical faecal occult blood test (iFOBT). It looks for tiny amounts of blood in your stool, far too small to see.
A positive result means blood was detected. It doesn't tell us where the blood came from or why. In 2024, about 6 in every 100 people who screened (5.8%) received a positive result.
Most positive results are not cancer
Of people assessed after a positive screen, about 1 in 29 is found to have bowel cancer. For the rest, the bleeding usually comes from:
Polyps (adenomas) — small growths that can turn into cancer over many years. Finding and removing them is how screening prevents bowel cancer, not just detects it.
Haemorrhoids or small tears (fissures) near the anus.
Diverticular disease or inflammation of the bowel lining.
A positive test is not a diagnosis. It's a signal to look — and a colonoscopy is how we look.
How likely is a polyp?
Polyps are the most common finding after a positive test, and they're the reason the colonoscopy matters so much:
About half of people having a colonoscopy after a positive screening test have at least one adenoma (a polyp that can become cancerous over time) found, and usually removed on the spot.
They become more common with age. The chance of finding polyps rises steadily from the late 40s into the 70s.
They're more common in men than in women.
For most people, finding a polyp simply means it's removed during the procedure and a follow-up colonoscopy is planned. Removing polyps is how screening prevents bowel cancer from developing in the first place.
Why the next step is a colonoscopy — not another kit
Don't repeat the kit. Bleeding from polyps and cancers comes and goes, so a negative second test doesn't cancel out the first.
Don't assume it's haemorrhoids, even if you know you have them. The only way to be sure is to look.
A colonoscopy examines the whole large bowel, and polyps can usually be removed and samples taken during the same procedure.
How soon should it happen?
Australian guidelines recommend a colonoscopy within 30 days of a positive screening result. In reality, only about 1 in 7 Australians (14.6% in 2024) achieved this, and median waits were measured in months. So don't put it off: see your GP within days and book promptly.
What the colonoscopy involves
Preparation: a low-residue diet and a bowel preparation drink to clear the bowel, so nothing is missed. You'll receive clear written instructions.
Sedation: you're given sedation by an anaesthetist, so most people are comfortable and remember little of the procedure.
The procedure: usually 20–40 minutes, as a day procedure. You go home the same day.
Afterwards: someone must take you home, and you shouldn't drive, work or sign legal documents for 24 hours.
Results: the findings are explained on the day; any tissue results usually follow within 1–2 weeks.
What happens after
Nothing significant found: you'll be advised when your next check is due — often a return to routine screening.
Polyps removed: a follow-up (surveillance) colonoscopy is scheduled based on the number, size and type of polyps.
Cancer found: screen-detected cancers are more often found at an early stage, when treatment works best. You'll be referred promptly to a specialist surgical and cancer team.
Common questions
I feel completely well — do I still need a colonoscopy?
Yes. Early polyps and bowel cancers usually cause no symptoms at all. That's exactly why screening exists.
Can I just do the test again?
No. A repeat negative test doesn't rule anything out after a positive one.
Do I need a referral?
Yes — see your GP, who will refer you to a gastroenterologist for colonoscopy.
Will Medicare cover it?
Medicare rebates apply to the specialist consultation and the procedure. Out-of-pocket costs depend on the hospital and your health fund — our rooms can give you an estimate before you book.
Getting your colonoscopy with Dr Jeffrey Tu
Dr Tu consults at The Mater Hospital, Wollstonecraft and Northern Beaches Hospital, Frenchs Forest, and performs colonoscopy at The Mater Hospital and Dee Why Endoscopy — so patients from the North Shore and Northern Beaches can be assessed and have their procedure close to home.
Patients: ask your GP for a referral, then call our rooms on 02 7245 8903. Please mention it's for a positive screening test.
GPs: refer via Healthlink (shoregtr), fax 02 7245 8906, or the online referral form on our Northern Beaches Hospital page.
Not screened yet? People aged 50–74 are mailed a free kit every 2 years. If you're 45–49 you can request your first kit online or on 1800 627 701. Read our guide: Bowel cancer screening: who needs what, and when.
Urgent symptoms: heavy bleeding, dizziness, severe abdominal pain or feeling very unwell needs same-day medical care — go to your nearest emergency department or call 000.
Sources
This article is general information and doesn't replace advice from your own doctor.
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