FIT Test Contraindications
The FIT test has no absolute contraindications for its intended use as a colorectal cancer screening tool in asymptomatic, average-risk individuals, but it should NOT be used in symptomatic patients, those with recent colonoscopy, or in acute care settings (ED/inpatient). 1, 2
When FIT Should NOT Be Used
Inappropriate Clinical Settings
- Symptomatic patients: FIT is contraindicated in patients with GI symptoms (rectal bleeding, diarrhea, weakness, abdominal pain). These patients require direct diagnostic evaluation, not screening tests 2
- Emergency department or inpatient settings: Studies demonstrate 100% inappropriate use when ordered in acute care settings, leading to unnecessary interventions and prolonged hospitalizations 2
- Recent colonoscopy: FIT should not be performed within 5 years of a colonoscopy with adequate bowel preparation 3. Among veterans who had both procedures, 88% of FIT tests following colonoscopy were judged inappropriate 3
Patient-Related Factors
While the 2017 Multi-Society Task Force guidelines 1 do not list specific patient contraindications, the following situations make FIT inappropriate:
- Active upper or lower GI bleeding: Symptomatic bleeding requires diagnostic workup, not screening
- Known colorectal pathology: Patients with established inflammatory bowel disease, known polyps, or previous CRC need surveillance colonoscopy, not FIT
- High comorbidity burden: Recent data shows 54.4% of FIT-positive patients were ineligible for follow-up procedures due to contraindications related to severe comorbidities 4
Critical Implementation Caveats
No Dietary or Medication Restrictions Required
The Task Force strongly recommends that patients NOT adjust diet or medications to complete FIT 1. This is a common pitfall—unlike older guaiac-based tests, FIT does not require:
- Avoiding red meat
- Stopping NSAIDs or anticoagulants (though anticoagulants are associated with positive results 2)
- Dietary modifications
Sample Collection Requirements
- Use spontaneously passed stool specimens only—NOT digital rectal examination samples 1
- Programs need not adjust distribution based on ambient temperature 1
The Positive FIT Mandate
When FIT is positive, colonoscopy is the ONLY recommended follow-up test (strong recommendation, moderate evidence) 1. This is non-negotiable:
- 27.5% of veterans with positive FIT failed to complete colonoscopy within one year 3
- Positive predictive value for CRC ranges from 0.9% at low hemoglobin levels (20-39.9 μg/g) to 6.7% at ≥200 μg/g 5
- All positive FIT results require colonoscopy regardless of quantitative value, as neoplastic findings occur across the entire spectrum 5
Common Pitfalls to Avoid
Ordering FIT in symptomatic patients: This is the most common misuse—negative FIT may falsely reassure clinicians about worrisome symptoms requiring investigation 2
Failing to ensure annual repeat testing: After negative FIT, only 62.4% of eligible patients underwent repeat testing as recommended 3
Using FIT too soon after colonoscopy: This represents 1.6% of all FITs performed but 88% were inappropriate 3
Ordering upper GI evaluation for positive FIT with negative colonoscopy: In the absence of upper GI symptoms, this is not recommended 1