From the Guidelines
No, FIT (Fecal Immunochemical Test) and high sensitivity fecal occult blood test (FOBT) are not the same, though they serve similar purposes in colorectal cancer screening. FIT specifically detects human hemoglobin using antibodies, making it more specific for lower gastrointestinal bleeding, as noted in the study by Allison et al 1. It requires no dietary or medication restrictions before testing and typically involves collecting only one stool sample. High sensitivity FOBT, on the other hand, detects the presence of blood through a chemical reaction (guaiac-based) that can be affected by certain foods and medications, requiring dietary restrictions before testing, as seen in the comparison between FIT and gFOBT in the study by Smith et al 1. It also typically requires multiple stool samples.
Key Differences
- FIT is more specific for human hemoglobin, reducing false positives from dietary sources
- FIT requires less preparation and typically only one stool sample, improving patient compliance
- High sensitivity FOBT is more prone to false positives due to its chemical reaction mechanism and requires more stringent dietary restrictions
Evidence Supporting FIT
Studies have consistently shown that FIT has superior test performance characteristics compared to gFOBT, including higher sensitivity and specificity for detecting colorectal cancer and advanced neoplasia, as demonstrated in the studies by Park et al 1 and Brenner and Tao 1. The American Family Physician recommendation statement also notes that FIT has improved accuracy compared to gFOBT 1.
Clinical Implications
Given the evidence, FIT is the preferred screening method for colorectal cancer due to its improved specificity, ease of use, and higher patient compliance. This is in line with the recommendations from the US Multi-Society Task Force on Colorectal Cancer 1 and the American Family Physician 1. The choice between FIT and high sensitivity FOBT should be based on individual patient factors and screening program preferences, but FIT is generally considered the better option for its accuracy and patient-friendly design.
From the Research
Comparison of Fecal Immunochemical Test (FIT) and High-Sensitivity Fecal Occult Blood Test (FOBT)
- The Fecal Immunochemical Test (FIT) and high-sensitivity Fecal Occult Blood Test (FOBT) are not the same, although both are used for colorectal cancer screening 2, 3, 4, 5, 6.
- FIT specifically detects human hemoglobin in stool samples, whereas FOBT detects heme 3, 4.
- Studies have shown that FIT has a higher sensitivity for detecting advanced colorectal neoplasia and cancer compared to FOBT 2, 3, 5, 6.
- The specificity of FIT is generally lower than FOBT, but still relatively high 2, 5, 6.
Key Differences
- FIT is more sensitive than high-sensitivity FOBT for detecting advanced colorectal neoplasia 2, 3, 5, 6.
- FIT has a higher detection rate of cancer and advanced adenoma compared to FOBT 3, 6.
- FIT is simpler to use and improves patient participation rates compared to FOBT 3, 4.