Management of a Positive Fecal Immunochemical Test (FIT)
A patient with a positive FIT requires colonoscopy as the sole follow-up examination, scheduled within 3 months and completed no later than 6 months after the positive result. 1, 2, 3
Primary Management: Colonoscopy
Colonoscopy is the only recommended follow-up test for all screen-eligible individuals with positive FIT results, as stated by the U.S. Multi-Society Task Force on Colorectal Cancer with strong evidence supporting this approach. 1, 2, 3
Why Colonoscopy is Optimal:
- Colonoscopy directly evaluates the entire colorectal mucosa and simultaneously allows removal of significant neoplasia when detected, making it superior to all other diagnostic modalities. 1, 2
- The positive predictive value for significant neoplasia is high when FIT returns positive, justifying immediate colonoscopic evaluation regardless of other clinical features like anemia. 1, 3
Critical Timing Requirements
Schedule colonoscopy within 3 months of the positive FIT result, with completion no later than 6 months. 2, 3
Evidence for Timing:
- Delays beyond 6 months are associated with significantly increased risk of colorectal cancer (OR 1.31) and advanced-stage disease (OR 2.09). 4
- Delays beyond 10-12 months dramatically increase risk of any colorectal cancer (OR 1.48-2.25) and advanced-stage disease (OR 1.97-3.22). 5
- Healthcare systems should aim for ≥95% of follow-up colonoscopies performed within 6 months, with at least 80% offered appointments within 3 months. 1, 2, 3
- Follow-up at 2-9 months shows no significant difference in cancer risk compared to 8-30 days, but risk increases substantially after 10 months. 5
What NOT to Do
Do NOT routinely order upper endoscopy (EGD) based solely on a positive FIT. 2
Upper GI Evaluation Guidelines:
- In the absence of iron deficiency anemia or signs/symptoms of upper gastrointestinal pathology, a positive FIT with negative colonoscopy should NOT prompt upper gastrointestinal evaluation. 1, 2
- Consider EGD only if iron deficiency anemia is present at the time of positive FIT, or if active upper GI symptoms exist (dysphagia, persistent nausea/vomiting, epigastric pain). 2
- Do NOT delay colonoscopy to perform EGD first unless upper GI symptoms are present. 2
Special Circumstances
Recent Prior Colonoscopy:
If a patient has a positive FIT but underwent colonoscopy recently (before they would be due for repeat examination), generally offer repeat colonoscopy. 1
Additional considerations include:
- Clinical context (other worrisome signs, symptoms, or laboratory values) 1
- Patient risk factors for advanced neoplasia 1
- Prior colonoscopy quality (poor bowel preparation, low adenoma detection rate) 1
No Medication or Dietary Adjustments Needed:
Patients do NOT need to adjust diet, anticoagulation, or antiplatelet agents when using FIT-based screening. 1
- Unlike guaiac-based tests, FIT is not confounded by dietary intake of foods with peroxidase activity. 1
- Aspirin, warfarin, and clopidogrel do not negatively impact FIT test characteristics and may actually improve sensitivity without decreasing specificity. 1
System-Level Implementation
Tracking and Outreach:
Programs should track all positive FIT results and attempt outreach in 100% of patients within ≤2 weeks of test results. 1
- System-level navigation programs that contact patients by telephone to schedule appointments increase adherence to colonoscopy follow-up. 1
Common Barriers to Address:
Patient-related factors account for 49.3% of non-adherence, with patient decline being the most common reason (35.2%). 6
COVID-19 Pandemic Context
During resource-limited situations (such as the COVID-19 pandemic), colonoscopy following positive FIT can be delayed up to 6 months without negatively impacting patient outcomes. 1
- Delays of 7-9 months show nonsignificant increased risk, but delays beyond 12 months show profound risk increase. 1
- Colonoscopy for positive FIT is considered non-time-sensitive and can be delayed beyond 8 weeks during pandemics or resource constraints. 1
Key Pitfalls to Avoid
- Never use FIT as a diagnostic test in patients with visible blood in stool—these patients require direct colonoscopy without preliminary FIT testing. 7
- Never assume a negative colonoscopy after positive FIT requires upper GI evaluation unless iron deficiency anemia or upper GI symptoms are present. 1, 2
- Never delay colonoscopy beyond 6 months under normal circumstances, as cancer risk and stage progression increase significantly. 4, 5
- Never falsely reassure patients that delays are acceptable—median time to colonoscopy should be approximately 83 days, with most completed within 3 months. 6, 4