What are the next steps after a negative Fecal Immunochemical Test (FIT) result for occult blood?

Next Steps After a Negative FIT Result

After a negative Fecal Immunochemical Test (FIT) result, patients should be informed of the appropriate recall interval for future screening, which is typically annual testing for average-risk individuals. 1

Understanding Negative FIT Results

A negative FIT result indicates that no significant amount of human hemoglobin was detected in the stool sample, suggesting a lower likelihood of colorectal bleeding. However, it's important to understand that:

• FIT is designed primarily to detect colorectal cancer (CRC), with limited diagnostic accuracy for adenomas 1
• The sensitivity of FIT for colorectal cancer is approximately 92% in clinical practice, meaning about 8% of cancers may be missed 2
• FIT is more specific for lower gastrointestinal bleeding compared to guaiac-based tests 1

Recommended Follow-Up Protocol

For Average-Risk Individuals:

1. Annual repeat testing

   • Patients should be clearly informed that annual testing is necessary to achieve the fullest potential of FIT screening 1
   • The screening program should document how recall will be made 1

2. Patient notification

   • Results should be communicated to patients within 2 weeks of the test 1
   • Clear explanation of what the negative result means and when to repeat testing

Special Considerations:

• Persistent symptoms: If a patient has a negative FIT but continues to have concerning symptoms (change in bowel habits, iron deficiency anemia), further evaluation may be warranted regardless of the negative FIT result
• Risk stratification: Consider that certain factors may affect FIT performance:
  • Male sex
  • Family history of colorectal cancer
  • Smoking status
  • Use of aspirin or NSAIDs 1

Quality Assurance Measures

For optimal screening outcomes, healthcare systems should implement:

• Objective metrics to monitor program compliance 1
• Systems to ensure adherence to appropriate screening intervals 1
• Tracking of key performance indicators including participant adherence and punctual reporting of test results 1

Potential Pitfalls to Avoid

1. Overreliance on a single negative result

   • A single negative FIT does not rule out colorectal neoplasia
   • Research shows that individuals with FIT values that are detectable but below the positivity threshold (negative but not zero) have an increased risk of advanced neoplasia in subsequent screenings 3

2. Poor follow-up systems

   • Lack of systematic recall can lead to missed opportunities for annual screening
   • Screening programs should have fastidious systems to ensure compliance to appropriate intervals 1

3. Ignoring persistent symptoms

   • A negative FIT should not override clinical judgment when patients present with persistent symptoms suggestive of colorectal pathology

Conclusion for Clinical Practice

For the patient with a negative FIT result from 3 weeks ago, the appropriate next step is to:

1. Document the negative result
2. Inform the patient that this result is reassuring but not definitive
3. Schedule the next annual FIT screening in approximately 11-12 months
4. Ensure the patient understands the importance of completing annual testing
5. Address any ongoing symptoms that prompted the initial testing, as FIT is not a perfect test