Rapid diagnostic tests for group A streptococcal pharyngitis: a meta-analysis

Abstract

Background and objective: Effective management of group A streptococcal (GAS) pharyngitis is hindered by impracticality of the gold standard diagnostic test: throat culture. Rapid antigen diagnostic tests (RADTs) are a promising alternative, although concerns about their sensitivity and specificity, and variation between test methodologies, have limited their clinical use. The objective of this study was to perform a systematic review with meta-analysis of the diagnostic accuracy of RADTs for GAS pharyngitis.

Methods: Medline and Embase from 1996 to 2013 were used as data sources. Of 159 identified studies, 48 studies of diagnostic accuracy of GAS RADTs using throat culture on blood agar as a reference standard were selected. Bivariate random-effects regression was used to estimate sensitivity and specificity with 95% confidence intervals (CIs). Additional meta-analyses were performed for pediatric data.

Results: A total of 60 pairs of sensitivity and specificity from 48 studies were included. Overall summary estimates for sensitivity and specificity of RADTs were 0.86 (95% CI 0.83 to 0.88) and 0.96 (95% CI 0.94 to 0.97), respectively, and estimates for pediatric data were similar. Molecular-based RADTs had the best diagnostic accuracy. Considerable variability exists in methodology between studies. There were insufficient studies to allow meta-regression/subgroup analysis within each test type.

Conclusions: RADTs can be used for accurate diagnosis of GAS pharyngitis to streamline management of sore throat in primary care. RADTs may not require culture backup for negative tests in most low-incidence rheumatic fever settings. Newer molecular tests have the highest sensitivity, but are not true point-of-care tests.

Keywords: group A streptococcus; pharyngitis; rapid test; sensitivity; specificity.