Evaluation of Diagnostic Performance of the Transferrin/FOB Combo Rapid Test Cassette (Feces) for Gastrointestinal Bleeding

The Transferrin/FOB Combo Rapid Test Cassette (Feces) is a chromatographic immunoassay designed for the qualitative detection of human hemoglobin and transferrin in human fecal specimens. This study aims to evaluate the consistency between test results of Transferrin/FOB Combo rapid test produced by CITEST DIAGNOSTCS INC. and the contrast test device, and evaluate its clinical application ability through testing on certain quantity of representative specimens and through scientific and reasonable statistic analysis on the results. A total of 436 fecal specimens from both symptomatic and asymptomatic individuals undergoing endoscopic examination were tested. The reference method was a commercially available rapid test (W.H.P.M Inc. Transferrin/Hemoglobin FOB Combo Rapid Test). For FOB detection, the relative sensitivity was 97.9% (95%CI: 94.1%~99.6%), relative specificity was 99.7% (95%CI: 98.1%~99.9%), and accuracy was 99.1% (95%CI: 97.7%~99.8%), with a Kappa value of 0.98 indicating excellent consistency. For transferrin detection, the relative sensitivity was 98.9% (95%CI: 94.1%~99.9%), relative specificity was 99.4% (95%CI: 97.9%~99.9%) and accuracy was 99.3% (95%CI: 98.0%~99.9%), with a Kappa value of 0.98. The LOD was 50 ng/mL or 6 μg/g feces for FOB and 40 ng/mL or 4 μg/g feces for transferrin. Intra-assay and inter-assay precision were excellent (>99% correct identification). No cross-reactivity was observed with common interfering substances. These findings indicate that the Transferrin/FOB Combo Rapid Test Cassette is a reliable, rapid and practical tool for simultaneous detection of FOB and transferrin, aiding in the timely diagnosis of gastrointestinal bleeding, including upper and lower gastrointestinal disorders.