Evaluation of Rapid Diagnostic Tests for Typhoid Fever

Abstract

Laboratory diagnosis of typhoid fever requires isolation and identification of Salmonella enterica serotype Typhi. In many areas where this disease is endemic, laboratory capability is limited. Recent advances in molecular immunology have led to the identification of sensitive and specific markers for typhoid fever and technology to manufacture practical and inexpensive kits for their rapid detection. We evaluated three commercial kits for serologic diagnosis of typhoid fever. Patients presenting with > 4 days of fever were enrolled at two hospitals in Southern Vietnam. Cases were patients with serotype Typhi isolated from blood samples, and controls were patients with other laboratory-confirmed illnesses. Serotype Typhi isolates were confirmed and tested for antimicrobial susceptibility at the Pasteur Institute in Ho Chi Minh City. The Widal test was run at the hospitals and the Pasteur Institute. Sera were shipped frozen to the Centers for Disease Control and Prevention and tested by using Multi-Test Dip-S-Ticks, TyphiDot, and TUBEX to detect immunoglobulin G (IgG), IgG and IgM, and IgM, respectively. Package insert protocol instructions were followed. We enrolled 59 patients and 21 controls. The sensitivity and specificity findings were as follows: 89 and 53% for Multi-Test Dip-S-Ticks, 79 and 89% for TyphiDot, 78 and 89% for TUBEX, and 64 and 76% for Widal testing in hospitals and 61% and 100% for Widal testing at the Pasteur Institute. For all assays, the sensitivity was highest in the second week of illness. The Widal test was insensitive and displayed interoperator variability. Two rapid kits, TyphiDot and TUBEX, demonstrated promising results.

Comparative evaluation of slide agglutination and Widal tube agglutination test in detecting enteric fever among patients attending a tertiary care hospital in North India

“…The World Health Organization (WHO) estimate for annual global incidence of typhoid fever is about 21 million cases of which more than 13 million cases occurring in Asia alone. [1][2][3] Without effective treatment, typhoid fever has a case-fatality rate of 10-30%. This number is reduced to 1-4% in those receiving appropriate therapy.…”

Typhoid fever: misuse of Widal test in Libya

“…The TUBEX commercial kit which detected IgM antibodies appeared to provide the most accurate results but has some limitations [23]. These new commercially available typhoid rapid antibody tests have shown variable performance [24][25][26] and have not fully been evaluated in Africa [27][28][29] (Table 1).…”

Clinical profile of enteric fever in tertiary care hospital of Kashmir

“…20 The mean fever clearance time with ceftriaxone used as single therapy observed in our study was 4. days (95% CI 3.7, 4.7 days) as against 6.1 days in literature. 4 Receipt of antibiotic therapy prior to admission was found to have no significant impact on the time to defervescence. Our study however suggest that combination therapy may be superior to single drug therapy, but we did not observe any significant difference in the time to defervescence in those patients who received ceftriaxone alone or in combination with azithromycin.…”

“…Blood culture is the 'gold standard' for diagnosis and also gives information about antibiotic sensitivity of the isolate. 3,4 However, prior oral antibiotics use and the cost of cultures, limits its use in the diagnostic approach. The Widal test is very commonly used in our set up but has very variable sensitivity and specificity and problems in interpretation.…”