Fecal Immunochemical Test Positivity Thresholds: An International Survey of Population-Based Screening Programs

Area of Science:

• Gastroenterology
• Oncology
• Public Health

Background:

• Fecal immunochemical test for hemoglobin (FIT) is a key non-invasive tool for population-based colorectal neoplasia screening.
• Current FIT positivity thresholds lack well-documented rationales, necessitating an understanding of global practices.
• An international survey was conducted to assess FIT usage, thresholds, and their underlying rationale in screening programs.

Purpose of the Study:

• To document the global usage of different FIT brands in organized screening programs.
• To identify the range of fecal hemoglobin (f-Hb) positivity thresholds currently applied.
• To understand the rationale behind the selection of specific FIT positivity thresholds.

Main Methods:

• An international electronic survey was distributed to members of the World Endoscopy Organization CRC Screening Committee.
• Responses were gathered from 63 individuals across 38 locations in 28 countries.
• A follow-up survey on technical issues was conducted with 17 sites from 13 countries.

Main Results:

• Quantitative FITs from four major manufacturers are in use globally.
• FIT positivity thresholds varied significantly, ranging from 8.5 to 120 µg hemoglobin/g feces, with 20 µg/g being common.
• The primary rationales for threshold selection were maximizing colorectal neoplasia sensitivity and aligning with colonoscopy resource availability.

Conclusions:

• A wide spectrum of FIT positivity thresholds is currently employed in international colorectal cancer screening programs.
• Adjusting FIT positivity thresholds allows programs to optimize outcomes within resource constraints.
• Future screening tests should allow for flexible threshold adjustments, especially those utilizing novel biomarkers.