Sensitivity and specificity of HAT Bioline Abbott® 2.0 and HAT Sero K-Set CORIS® 2.0 for human African trypanosomiasis in the Kasai-Oriental province, Democratic Republic of the Congo: a retrospective diagnostic accuracy study

Abstract

Abstract Background Human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense has declined substantially in recent years, with many endemic areas now reporting very low prevalence levels as countries move toward elimination. In the Democratic Republic of the Congo (DRC), rapid diagnostic tests (RDTs) are increasingly used in surveillance and elimination programs; however, their performance in low-prevalence settings remains critical. This study evaluated and compared the diagnostic accuracy of two second-generation RDTs; HAT Bioline Abbott ® 2.0 and HAT Sero K-Set CORIS ® 2.0; using trypanolysis as the reference standard. Methods A retrospective diagnostic accuracy study was conducted on 447 archived plasma samples (227 confirmed HAT cases and 220 controls) from a previous study in the DRC. Each sample was tested with both RDTs and trypanolysis. Sensitivity, specificity, predictive values, likelihood ratios, Cohen’s kappa coefficient, and Youden’s index were calculated with 95% confidence intervals. Paired comparisons were performed using McNemar’s χ 2 test, with statistical significance set at p < 0.05. Results HAT Bioline Abbott ® 2.0 showed a sensitivity of 85.2% (95% CI 80.4–90.0) and specificity of 72.2% (95% CI 66.4–77.9). The positive predictive value (PPV) was 73.1% (95% CI 67.5–78.6) and the negative predictive value (NPV) was 84.7% (95% CI 79.7–89.6). HAT Sero K-Set CORIS ® 2.0 demonstrated a sensitivity of 90.0% (95% CI 85.2–93.4) and a higher specificity of 88.2% (95% CI 83.5–91.7). The PPV was 87.1% (95% CI 82.0–90.9) and the NPV was 90.9% (95% CI 86.4–93.9). HAT Sero K-Set CORIS ® 2.0 showed stronger agreement with trypanolysis (κ = 0.78) and a higher Youden’s index (0.78) than Abbott ® 2.0 (κ = 0.57; Y = 0.57). Conclusions In this retrospective study, HAT Sero K-Set CORIS ® 2.0 demonstrated higher diagnostic accuracy under controlled laboratory conditions than HAT Bioline Abbott ® 2.0. Although both RDTs demonstrated acceptable sensitivity, neither achieved the specificity threshold (> 95%) recommended for surveillance and elimination verification in low-prevalence settings. These findings highlight the importance of optimizing specificity in serological screening tools as countries progress toward HAT elimination.