A Study of Immunochromatographic Fecal Occult Blood Test Methods

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.