title: Comparative evaluation of two rapid Salmonella-IgM tests and blood culture in the diagnosis of enteric fever.
abstract: OBJECTIVE
  Enteric fever is a major public health problem in developing countries like India. An early and accurate diagnosis is necessary for a prompt and effective treatment. We have evaluated the diagnostic accuracy of two Rapid Salmonella-IgM tests (Typhidot-IgM and Enteroscreen-IgM) as compared to blood culture in rapid and early diagnosis of enteric fever.
  
  
  METHODS
  A total of 2,699 patients' serum samples were tested by Rapid Salmonella-IgM tests and blood culture. Patients were divided into two groups. Test group - patients with enteric fever and blood culture positives for Salmonella Typhi; and three types of Controls, i.e. patients with non-enteric fever illnesses, normal healthy controls and patients positive for S. Paratyphi- A. In addition to this we have also evaluated the significance of positive Salmonella-IgM tests among blood culture-negative cases.
  
  
  RESULTS
  The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Typhidot-IgM test and Enteroscreen-IgM test considering blood culture as gold standard were 97.29% and 88.13%, 97.40% and 87.83%, 98.18% and 92.03%, 96.15% and 82.27%, respectively. Typhidot-IgM test was found to be significantly more sensitive and specific as compared to Enteroscreen-IgM. Among blood culture-negative patients, Rapid Salmonella-IgM tests detected 72.25% additional cases of enteric fever. Although the Rapid Salmonella-IgM tests are meant to diagnose S. Typhi only, but these tests detect S. Paratyphi- A also. Thirty-eight patients who were blood culture-positive for S. Paratyphi- A were also positive by Rapid Salmonella-IgM tests.
  
  
  CONCLUSIONS
  Rapid Salmonella-IgM tests offer an advantage of increased sensitivity, rapidity, early diagnosis and simplicity over blood culture.
authors: K J
authors: KJ
authors: Prasad
authors: J K
authors: JK
authors: Oberoi
authors: N
authors: N
authors: Goel
authors: Department of Clinical Microbiology and Immunology, Sir Ganga Ram Hospital, New Rajinder Nagar, New Delhi, India.
authors: C
authors: C
authors: Wattal
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D001431:Bacteriological Techniques / Q000379:methods*; D001769:Blood / Q000276:immunology / Q000382:microbiology; D042241:Early Diagnosis; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D007194:India; D012189:Retrospective Studies; D012485:Salmonella typhi / Q000254:growth & development / Q000276:immunology* / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods*; D013997:Time Factors; D014435:Typhoid Fever / Q000175:diagnosis*
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M