Rapid Diagnostic Test for Streptococcal Throat Infection in Egyptian Children

Background: Acute streptococcal pharyngitis represents a high prevalence in developing countries responsible of morbidity and mortality. Difficulty of prompt diagnosis is responsible for either inadequate therapy and subsequent rheumatic heart disease and renal failure, or abuse of antibiotics. Group AB hemolytic streptococcus (GABHS) detection by rapid tests is useful due to its rapidity and relative low cost. However sensitivity and specificity remain debatable. In Egypt, suspicion about its accuracy remains an important obstacle for mass utilization. The objective of this study was to evaluate the accuracy of a GABHS rapid antigen detection test kit, in comparison with oropharynx swab culture. Methods: Children aged 3 to 15 years with clinical diagnoses of non treated acute pharyngitis were recruited at public emergency health centers in a rural region eastern Cairo, with 95 patients, subjected to oropharyngeal swabs for rapid GABHS testing and conventional culture. Results: We observed sensitivity of 80.65%, specificity of 96.88%, a positive predictive value of 92.59%, a negative predictive value of 91.18% and a positive likelihood ratio for the rapid test used here, compared with throat culture. It was found a group of any 3 of fever, sore throat, dysphagia, cervical lymphadenopathy always present in false negative cases. Conclusions: The rapid test studied exhibited a good correlation with culture and is, therefore, of great use in clinical practice for detection of GABHS. Clinical picture has to be taken in consideration to increase the sensitivity of the test.