Diagnostic value of a single, pre-treatment Widal test in suspected enteric fever cases in the Philippines

Abstract

101 patients with a clinical suspicion of typhoid or paratyphoid (enteric) fever admitted to San Lazaro Hospital, Manila, Philippines, were studied by bacteriological culture of blood, rectal swab, urine and duodenal string capsule; 35 also had bacteriological culture of bone marrow aspirate. 44 of the patients were culture-confirmed as having enteric fever; the remainder were classified as non-enteric fever cases. Analysis of the pretreatment Widal agglutination titres of all patients revealed that using as a diagnostic criterion an antibody titre of greater than or equal to 1:80 to the O antigen of Salmonella typhi yielded a test specificity of 100%, although the corresponding sensitivity was only 64%. The sensitivity of the test could be increased to 80% by using different cut-off values for titres to flagellar antigens, but this concomitantly decreased the test specificity from 100 to 82%. The data indicate that a single pretreatment Widal test in suspected enteric fever cases is of definite diagnostic value, but that the results must be interpreted with caution and foreknowledge of the test's shortcomings and limitations.

Epidemiology, Clinical Presentation, Laboratory Diagnosis, Antimicrobial Resistance, and Antimicrobial Management of Invasive Salmonella Infections

“…In practice, the result from a single, acute-phase serum sample is often used, but false-negative and false-positive results are common. Knowledge of the background levels of antibodies in the local population may aid interpretation of the Widal test, and performance is best among patients with a high prior probability of enteric fever (242,243). For example, in a study from Vietnam using Widal test data from patients with typhoid fever and both febrile and healthy control participants, it was found that a cutoff titer of Ն200 for O agglutination or Ն100 for H agglutination would correctly diagnose 74% of blood culture-positive patients.…”

Typhidot M and Diazo test vis-à-vis blood culture and Widal test in the early diagnosis of typhoid fever in children in a resource poor setting

“…3 Widal test is now regarded as inaccurate, non-specific, poorly standardized and of limited diagnostic value. [4][5][6][7][8][9][10][11] To overcome such limitations, several assays and serological tests have been developed but none is found optimal. [12][13][14] A rapid serological/biochemical test to diagnose typhoid fever accurately at an early stage is thus currently needed.…”

The utility of diagnostic tests for enteric fever in endemic locations

“…The Widal test ideally requires both an acute and a convalescent-phase serum sample taken approximately 10 days apart, and a positive result is determined by a fourfold increase in antibody titer. However, antibody titers in infected patients often rise before the clinical onset, making it difficult to demonstrate the required fourfold rise between initial and subsequent samples for a confirmatory diagnosis [83][84][85]. Furthermore, in practice, the result of a single, acutephase serum sample is often used to help patient management and, although useful in some cases, a single serum result may be confusing in others [74,80,81,[85][86][87].…”