Comparative Evaluation of Typhidot IgM and Widal Tests for Typhoid Fever Diagnosis in a Tertiary Care Setting in Delhi, India

Background: Typhoid fever remains a significant public health challenge in developing countries. Accurate and timely diagnosis is crucial for effective management and control. This study aimed to compare the diagnostic performance of Typhidot IgM and Widal tests in a clinical setting in Delhi, India.
Methods: We conducted a retrospective analysis of data from patients with suspected typhoid fever at G.B. Pant Hospital from January 2024 to August 2024. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic (ROC) analysis were performed for both tests, using blood culture as the gold standard where available. In the absence of blood culture results, diagnosis was based on clinical criteria and response to treatment.
Results: Of the 412 patients included, 137 (33.3%) were confirmed positive for typhoid fever. Typhidot IgM demonstrated higher sensitivity (91.2% vs. 69.3%, p<0.001) and specificity (94.5% vs. 83.6%, p<0.001) compared to the Widal test. The PPV and NPV for Typhidot IgM were 89.4% and 95.5%, respectively, while for the Widal test, they were 68.7% and 84.1%. The area under the ROC curve (AUC) for Typhidot IgM was 0.928 (95% CI: 0.900-0.956), which was significantly higher than the AUC of 0.764 (95% CI: 0.714-0.815) for the Widal test (p<0.001).
Conclusion: Typhidot IgM showed superior diagnostic performance compared to the Widal test for diagnosis of typhoid fever in this setting. The higher sensitivity, specificity, and AUC of Typhidot IgM suggest that it could be a more reliable tool for rapid and accurate diagnosis of typhoid fever, particularly in areas with high antibiotic use prior to presentation.