Fecal Immunochemical Test Sensitivity for Colorectal Cancer Detection

FIT Sensitivity and Specificity

The sensitivity of FIT for detecting colorectal cancer ranges from 73% to 88%, with a pooled sensitivity of approximately 79% (95% CI, 69-86%) for colorectal cancer detection and a specificity of 94% (95% CI, 92-95%) 1, 2, 3
FIT sensitivity varies considerably depending on the specific brand, cut-off value used, and number of samples collected 1, 2
When using colonoscopy as the reference standard, the overall sensitivity of one-time FIT screening for colorectal cancer is approximately 77% 1, 2
The FDA-cleared OC FIT CHEK has demonstrated a sensitivity of 74% and specificity of 96% for cancer detection in a large US study of 9,989 individuals 2
Quantitative FIT assays can be adjusted by altering the threshold for a positive result - lower cut-off values increase sensitivity but decrease specificity 1

FIT sensitivity for advanced adenomas is significantly lower than for cancer, ranging from approximately 22% to 40% depending on the test and cut-off value 1, 2, 4
In studies using colonoscopy as the gold standard, sensitivities for advanced adenoma ranged from 25% to 56%, with specificities from 68% to 96% 4, 5
Decreasing the hemoglobin cut-off value can increase sensitivity for advanced adenomas: in one study, decreasing the OC-Sensor FIT cut-off from 20 to 10 μg/g increased sensitivity from 29% to 35%, with a corresponding decrease in specificity from 97% to 93% 4

FIT has approximately twice the sensitivity of guaiac-based FOBT (gFOBT) for cancer detection (79% vs. 30-65%) 6, 7
In direct comparisons, FIT consistently demonstrates higher sensitivity than gFOBT: Park et al. found FIT sensitivity for cancer at 84.6% vs. gFOBT at 30.8% 7
FIT plus stool DNA testing (FIT-DNA) has higher sensitivity (92%) but lower specificity (84%) than FIT alone 3

The American Gastroenterological Association recommends FIT over gFOBT due to its superior sensitivity 6
FIT has poor sensitivity for sessile serrated polyps (approximately 5%), which is an important limitation 6
Multiple rounds of testing (annual or biennial) can improve cumulative sensitivity over time 4

The American Gastroenterological Association notes that if a patient has a positive FIT test, their chance of actually having colorectal cancer is approximately 2-12%, meaning that 88-98% of positive FIT results are NOT due to colorectal cancer 8

The specificity of FIT ranges from 91-96%, which means 4-9% of people without colorectal cancer will have a false-positive FIT result 9
In absolute numbers, among 100 people without advanced neoplasia, 4-9 will still test positive 9
The sensitivity of FIT for cancer is 73-88%, indicating that FIT catches most cancers 9
The specificity of FIT is 91-96%, indicating that FIT correctly identifies most people without disease 9

The American College of Gastroenterology recommends that when counseling a patient with a positive FIT, emphasize that colonoscopy is mandatory, which is a strong recommendation with moderate-quality evidence 8
The American Cancer Society advises against repeating the FIT, as this is inappropriate and delays necessary evaluation 10
The American Gastroenterological Association recommends against pursuing upper GI evaluation if colonoscopy is negative and there are no iron-deficiency anemia or upper GI symptoms 8
Delays in colonoscopy beyond 270 days significantly increase the risk of late-stage cancer, with an odds ratio of 1.48 11