Comparative study of Typhidot-M with Widal and blood culture in diagnosis of enteric fever

Abstract

Objective: To evaluate the diagnostic utility of Typhidot-M and Widal test in the early diagnosis of enteric fever (EF) in terms of sensitivity and specificity. Methods: The study included 270 children in the age group of 1-18 years admitted to the Department of Pediatrics from November 2012 to February 2014, with fever of 5 days or more and with clinical symptoms and signs suggestive of typhoid fever. Detailed history and clinical examination findings were recorded on a standard pro forma. Complete hemogram (hemoglobin, platelet count, and total and differential leukocyte count), Typhidot-M test, Widal tube test, and blood culture weredone on day 1 of admission. For Widal test, a titer of 1 in 160 or more for “O” agglutinins and a titer of 1 in 320 or more for “H” agglutinins were considered as positive results. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results: Of 270 children included in the study, Salmonella typhi was isolated from 82 samples (30.4%) and the remaining 188 (69.6%) were blood culture negative. Widal test was positive in 107 children (39.6%) and Typhidot-M was positive in 136 (50.4%). The sensitivity was 78%, specificity was 79.3%, PPV was 59.8%, and NPV was 91.4% for Widal test. Typhidot-M test had a sensitivity of 81.7%, specificity of 84.6%, PPV of 69.8%, and NPV of 91.4%. Conclusion: Prompt diagnosisof EF is essential for appropriate management and it is, therefore, important to have a satisfactory test to replace conventional tests used for diagnosis. The present study compares newer test (Typhidot-M) against conventional tests such as Widal test and blood culture, and it appears to be a practical alternative to Widal test in the early detection of EF even in the resource-poor laboratories as it neither requires much laboratory equipment nor laboratory expertise to conduct the test. This test can be done within 7 days of illness, but whenever feasible confirmation with blood culture is strongly recommended, especially with the well-documented presence of multidrug-resistant strains of salmonella typhi worldwide. However, both Widal and Typhidot-M appear to correlate less satisfactorily with blood culture, and thus, there is a need for developing a test which allows accurate and early diagnosis of EF to manage a child effectively and limit its morbidity and mortality.

A Cross-Sectional Comparative Study of the Performance of the Widal Test and the Typhidot Immunoassay for Typhoid Fever Diagnosis in the West Region of Cameroon

“…e majority of the participants were female, accounting for 67.38% (376/558) of the total sample. e majority of participants were in the age range [11][12][13][14][15][16][17][18][19][20] years (219/558, 39.27%) and were students. According to occupation, respondents that were students were more represented (47.67% (n = 266)), followed by participants working in the private sectors (25.80% (n = 144)).…”

“…The assay gives good results during early infections with a sensitivity of 68–95% and a specificity of 75–95% [ 15 , 16 ]. An increase in the negative predictive value is important in endemic areas [ 17 ]. Recommendations from the World Health Organization for typhoid rapid antibody testing [ 18 ] and some studies that have evaluated the Typhidot ability to detect antibodies have shown variations in sensitivity and specificity [ 15 ] in different settings.…”

A comparative study of the performance of the widal slide agglutination test and the typhidot immunoassay for the diagnosis of typhoid fever in the West Region of Cameroon.

“…The majority of the participants were female, accounting for 67.38% (376/558). The majority of participants were in the age range [11][12][13][14][15][16][17][18][19][20] years old (219/558, 39.27%), were students. According to occupation, respondent that were student was more represented (n= 266) with 47.67% follow by participants working in the private sectors (144) with 25.80%.…”

“…The assay gives good results during early infections with sensitivity of 68-95% and a speci city of 75-95% [15,16]. An increase of negative productive value is important in endemic areas [17]. According to recommendations from World Health Organization for typhoid rapid antibody testing [18] and some studies that have evaluated the typhidot ability to detect antibodies have shown variations in sensitivity and speci city [15] in different settings.…”

Evaluation of Diagnostic Accuracy of Typhidot Test Against Blood Culture in Diagnosis of Enteric Fever

“…The yield of blood culture is 90% in 1 st week, 75% in 2 nd week followed by reduction to 50% by 3 rd week and 25% by 4 th week 10 . Percentage of positive for blood culture is only 30 to 40 because number of patients start antibiotics before taking blood sample for culture 11 .…”