A study of immunochromatographic fecal occult blood test methods

Abstract

Background: The sensitivity of the commonly used immunochromatographic fecal occult blood test (iFOBT) is critical in the routine screening of digestive tract cancers. Objective: To determine whether the performance of the iFOBT might be improved by optimizing detergents and buffers in stool solution. Methods: We tested different buffers and detergents in stool solution. The specificity of the new solution condition was confirmed by dot immunoblotting. A total of 1122 clinical stool specimens were collected to evaluate the clinical application of this refined stool solution. Results: The different salts exerted minor effects; also, sodium dodecyl sulfate (SDS) prevented the test from working as designed. However, 1% Triton X-100 improved the sensitivity significantly, as confirmed by dot immunoblot testing. With 1% Triton X-100 in the stool solution, the rate of positive iFOBT results in patients with digestive tract cancers increased, from 40.4% to 49.4%. Conclusion: Use of 1% Triton X-100 improves the sensitivity of the iFOBT and thus, this substance should be routinely included in iFOBT for screening of digestive tract cancers.