A positive faecal immunochemical test (FIT) means you need a colonoscopy; repeating the stool test does not replace it [3]. In the Isfahan screening programme, only about 20% of people with a positive test had a colonoscopy, although polyps or cancer were found in 26% of those who did [1]. Colonoscopy later than 10 months was linked to a higher risk of cancer and of more advanced cancer [2].
Key points
- A positive test means a colonoscopy, not repeating the test and not waiting [3].
- Do it soon: a delay of more than 10 months was linked to more and more advanced cancer [2]; it is best to book within the first few weeks.
- Positive does not mean cancer: most people do not have cancer, and many only have polyps that are removed during the same colonoscopy [1].
One important step: do not put off the colonoscopy
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Show the result to your doctor or health centre
A positive test in a screening programme should be referred for colonoscopy [1].
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Book the colonoscopy
In a large study of 70,124 people with a positive test, colonoscopy within 9 months did not change the risk, but after 10 to 12 months the risk of cancer was 48% higher and the risk of advanced cancer about twice as high, and it rose further after 12 months [2].
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Do the bowel preparation fully
Follow the laxative and diet instructions before the colonoscopy exactly, so the doctor can see the whole bowel.
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Ask about the result and the next plan
If a polyp was removed, the doctor will tell you when the next colonoscopy is due based on the pathology result.
When should I contact a doctor?
The stool test is for people without symptoms. Bleeding from the bottom or blood in the stool, a lasting change in bowel habit, anaemia or unexplained weight loss should be checked at any age, even with a negative test (symptoms of bowel cancer (Persian)).
Frequently asked questions
Can I repeat the stool test instead of having a colonoscopy?
No. When a stool test is positive, screening is completed only by colonoscopy; a later negative test does not cancel the earlier positive result [3].
Maybe the blood is from piles. Is it still needed?
Yes. The test does not tell where the blood comes from, and only a colonoscopy can rule out polyps or cancer [3].
I am afraid of colonoscopy.
Colonoscopy is usually done with sedation and serious complications are rare (more about colonoscopy (Persian)). Removing polyps in the same session prevents cancer.
Notes for doctors (for physicians)
For physicians
The follow-up gap in Iran. In the Isfahan IraPEN FIT programme (2016 to 2019, ages 50 to 70), 345,207 people (about 40% of the target population) took part; 21,264 (6.1%) had a positive FIT and only about 20% of them had a colonoscopy with an available report; in this group 971 polyps (24%) and 110 cancers (3%) were found [1].
Timing of colonoscopy. In the Kaiser Permanente cohort (70,124 people), compared with 8 to 30 days, follow-up up to 9 months made no significant difference; at 10 to 12 months the OR for cancer was 1.48 (1.05 to 2.08) and for stage III–IV cancer 1.97 (1.14 to 3.42), and after 12 months 2.25 and 3.22 respectively [2]. Track follow-up actively: contact the patient, refer directly and record the result.
Scientific evidence
Related cancer types
References
3 referencesShow all references, 1 with a study cardClose the reference list
Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
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This page is based on reputable scientific sources and was last updated on 27 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
