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Updated: Aug 2, 2026
Determining the Reactivity and Titre of Serum using a Haemagglutination Assay
Published on: January 29, 2010
Determination of diagnostic Widal titres in Kumasi, Ghana
E H Frimpong1, P Feglo, M Essel-Ahun
1Department of Clinical Microbiology, School of Medical Sciences, University of Science and Technology, Kumasi-Ghana, Ministry of Health, Ghana.
Abstract:
Three hundred and seven healthy food handlers and 34 blood-culture positive enteric fever patients were screened for Salmonellae agglutinins using the Widal test. Of the 307 healthy food handlers, only 3 (1.0%) had an anti-O titre of > or = 1/160 and 8 (2.6%) an anti-H titre of > or = 1/320 for Salmonella typhi, but the majority, 214 (69.7%) and 149 (48.5%) had titres of < 1/20 for O and H agglutinins respectively. Similar agglutinin titres were also seen for S. Paratyphi A, B, and C. In the 34 enteric fever patients, for S typhi, based on anti-O titre of > or = 1/160, 25 persons showed a significant titre, a sensitivity of 73.5%, and a specificity of 99.0%. And 21 persons showed a significant titre of > or = 1/320 for anti-H, a sensitivity of 61.8% and a specificity of 97.4%. Based on these findings, titres of > or = 1/160 and > or = 1/320 for anti-0 and anti-H respectively, were considered diagnostic for enteric fever in Kumasi, Ghana.
Insights
The Widal test accurately diagnoses enteric fever in Kumasi, Ghana. Specific Salmonella typhi antibody titers are recommended for reliable results in this region.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Immunology
Background:
- Enteric fever, primarily caused by Salmonella Typhi, remains a significant public health concern globally.
- Accurate diagnostic tools are crucial for timely treatment and effective disease control, especially in resource-limited settings.
- The Widal test, a serological assay, is commonly used for diagnosing enteric fever but requires local validation.
Purpose of the Study:
- To evaluate the diagnostic performance of the Widal test for enteric fever in Kumasi, Ghana.
- To establish appropriate cut-off titers for anti-O and anti-H antibodies for Salmonella typhi in the study population.
- To determine the sensitivity and specificity of the Widal test in identifying enteric fever cases.
Main Methods:
- Screening of 307 healthy food handlers and 34 blood-culture confirmed enteric fever patients.
- Utilizing the Widal test to measure Salmonellae agglutinin titers (anti-O and anti-H) against Salmonella typhi and Salmonella paratyphi A, B, and C.
- Analyzing titer data to determine optimal diagnostic cut-offs and calculate test sensitivity and specificity.
Main Results:
- In healthy individuals, low titers (< 1/160 for anti-O, < 1/320 for anti-H) were prevalent, with only 1.0% and 2.6% showing elevated titers for S. typhi.
- In enteric fever patients, anti-O titers ≥ 1/160 showed 73.5% sensitivity and 99.0% specificity.
- Anti-H titers ≥ 1/320 demonstrated 61.8% sensitivity and 97.4% specificity for diagnosing enteric fever.
Conclusions:
- The Widal test is a valuable diagnostic tool for enteric fever in Kumasi, Ghana.
- Recommended diagnostic titers are anti-O ≥ 1/160 and anti-H ≥ 1/320 for Salmonella typhi.
- These validated cut-offs enhance the reliability of enteric fever diagnosis in the region.
