Management of Positive FIT Result
Colonoscopy is the mandatory next step after a positive FIT result and should be scheduled within 3 months, with completion no later than 6 months. 1, 2
Primary Recommendation: Colonoscopy Only
All screen-eligible individuals with a positive FIT require colonoscopy as the sole follow-up test, regardless of other clinical features. 1, 3 This is a strong recommendation based on moderate-quality evidence from the U.S. Multi-Society Task Force on Colorectal Cancer. 1
Why Colonoscopy is Optimal
- Colonoscopy directly evaluates the entire colorectal mucosa and simultaneously allows removal of significant neoplasia when detected. 1, 3
- The positive predictive value for significant neoplasia is high with a positive FIT (35% for high-risk polyps, 4.9% for colorectal cancer). 4
- Detection rates for advanced colorectal neoplasia range from 40-47% in FIT-positive patients. 5
Timing Requirements
Schedule colonoscopy within 3 months of the positive FIT result, with a maximum acceptable delay of 6 months. 2, 3
- Healthcare systems should aim for ≥95% of follow-up colonoscopies performed within 6 months. 2, 3
- At least 80% of patients should be offered appointments within 3 months. 2, 3
- Delays beyond 6 months are associated with increased risk of advanced adenomas, colorectal cancer, and advanced-stage disease. 2
- Risk of advanced colorectal neoplasia increases progressively with longer delays (17.2% at <30 days vs 27.2% at ≥180 days). 6
Special Circumstances
Patients with Recent Colonoscopy
Even if a patient had a colonoscopy within the past 3 years, repeat colonoscopy should generally be offered for a positive FIT. 1
- FIT has superior performance characteristics compared with guaiac-based tests, justifying repeat examination. 1
- The prevalence of colorectal cancer in FIT-positive patients with colonoscopy <3 years prior is 2.1%, and advanced colorectal neoplasia is 10.9%. 7
- Additional considerations include clinical context (worrisome signs, symptoms, laboratory values), patient risk factors for advanced neoplasia, and prior colonoscopy quality (bowel preparation adequacy, endoscopist's adenoma detection rate). 1
Upper Endoscopy Considerations
Do NOT routinely perform upper endoscopy (EGD) for a positive FIT with negative colonoscopy. 1, 3
- In the absence of iron-deficiency anemia or signs/symptoms of upper gastrointestinal pathology, a positive FIT and negative colonoscopy should not prompt upper gastrointestinal evaluation. 1, 3
- Consider EGD only if iron deficiency anemia is present at the time of positive FIT. 3, 5
- Consider EGD only if active upper GI symptoms exist (dysphagia, persistent nausea/vomiting, epigastric pain). 3
Common Pitfalls to Avoid
- Do not repeat FIT instead of proceeding to colonoscopy - colonoscopy is mandatory when FIT is positive. 5
- Do not reflexively order EGD based solely on positive FIT, as this leads to unnecessary procedures, increased costs, and patient burden without mortality or morbidity benefit. 3
- Do not delay colonoscopy to perform EGD first unless upper GI symptoms are present. 3
- Do not assume occult blood must be localized to upper versus lower tract - FIT is specifically designed to detect lower GI bleeding and has high positive predictive value for colorectal neoplasia. 3
No Dietary or Medication Restrictions
- Unlike guaiac-based tests, FIT testing is not confounded by dietary intake of foods with peroxidase activity. 1
- No dietary restrictions are necessary before or during FIT testing. 1