Diagnostic accuracy of rapid nucleic acid tests for group A streptococcal pharyngitis: systematic review and meta-analysis.

BACKGROUND Acute pharyngitis is one of the most common conditions in outpatient settings and an important source of inappropriate antibiotic prescribing. Rapid antigen detection tests (RADTs) offer diagnosis of group A streptococcus (GAS) at the point of care but have limited sensitivity. Rapid nucleic acid tests (RNATs) are now available; a systematic review of their accuracy is lacking. OBJECTIVES (1) To evaluate the accuracy of RNATs in patients with pharyngitis; (2) To explore test- and study-level factors that could explain variability in accuracy; (3) To compare the accuracy of RNATs with that of RADTs. DATA SOURCES MEDLINE, Embase, Web of Science (1990 - 2020). STUDY ELIGIBILITY CRITERIA Cross-sectional studies and randomized trials. PARTICIPANTS Patients with pharyngitis. Index test/s and reference standards: RNAT commercial kits compared to throat culture. METHODS We assessed risk of bias and applicability using QUADAS-2. We performed meta-analysis of sensitivity and specificity using the bivariate random-effects model. Variability was explored by subgroup analyses and meta-regression. RESULTS We included 38 studies (46 test evaluations; 17,411 test results). RNATs were most often performed in a laboratory. The overall methodological quality of primary studies was uncertain because of incomplete reporting. RNATs had a summary sensitivity of 97.5% (95% CI: 96.2-98.3) and a summary specificity of 95.1% (93.6-96.3). There was low variability in estimates across studies. Variability in sensitivity and specificity was partially explained by test type (p<0.05 for both). Sensitivity analyses limited to low risk of bias studies showed robust accuracy estimates. RNATs were more sensitive than RADTs (13 studies; 96.8% vs. 82.3%, p=0.004); there was no difference in specificity (p=0.92). CONCLUSIONS The high diagnostic accuracy of RNATs may allow their use as stand-alone tests to diagnose GAS pharyngitis. Based on direct comparisons, RNATs have greater sensitivity than RADTs and equal specificity. Further studies should evaluate RNATs in point-of-care settings.