Comparative Evaluation of Immunochromatographic IgG & IgM card test with Widal Tube Agglutination test for diagnosis of Enteric Fever

Abstract

Introduction: Enteric fever remains a major public health concern in endemic regions, with diagnostic challenges due to nonspecific clinical presentation. Blood culture is the gold standard but is limited by availability and turnaround time. Serological tests such as Widal and rapid immunochromatographic assays are widely used, though their diagnostic accuracy varies.

Aim: To evaluate the diagnostic performance of the rapid Salmonella Typhi IgM/IgG immunochromatographic card test in comparison with the conventional Widal tube agglutination test, using blood culture as the gold standard.

Materials and Methods: This cross sectional prospective study included 147 patients with suspected enteric fever. Demographic and clinical data were recorded. Each sample was tested by Widal tube agglutination, Advantage Typhi IgM/IgG card test, and blood culture. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated.

Results: Fever was present in all patients (100%), followed by headache (76.19%) and abdominal pain (66.67%). The Widal test showed sensitivity of 82.6%, specificity of 99.2%, PPV of 95%, NPV of 96.8%, and accuracy of 96.1%. The immunochromatographic card test demonstrated higher sensitivity (95.65%) but lower specificity (90.91%), with PPV of 76.67%, NPV of 98.35%, and accuracy of 91.84%.

Conclusion: The immunochromatographic card test is highly sensitive and suitable for rapid screening, while the Widal test remains more specific and useful for confirmation. Combined use of both tests can enhance diagnostic accuracy and improve patient management in endemic settings.