A comparison of the Quidel Solana GAS assay, the Luminex Aries Group A Strep assay and the Focus Diagnostics Simplexa Group A Strep Direct assay for detection of Group A Streptococcus in throat swab specimens

Abstract

We compared three commercially available group A Streptococcus (GAS) nucleic acid amplification tests, the Quidel Solana GAS assay, the Luminex Aries Group A Strep assay and the Focus Diagnostics Simplexa Group A Strep Direct assay, with GAS bacterial culture. A true positive result was defined as one positive by culture or positive by ≥2/3 molecular methods. Two hundred eighty-seven throat swabs (207 children, 80 adults) were collected. The sensitivity of culture was 84.8% (95% CI 77.7–90.3%) with a specificity of 100% (95% CI 97.5–100%). The Solana assay sensitivity was 94.2% (95% CI 88.9–97.5%) with a specificity of 98.7% (95% CI 95.2–99.8%). Simplexa assay sensitivity was 99.3% (95% CI 96.0–99.9%) with a specificity of 95.3% (95% CI 90.6–98.1%). Aries assay sensitivity was 96.4% (95% CI 91.8–98.8%) with a specificity of 98.0% (95% CI 94.2–99.6%). In summary, all the molecular methods evaluated showed high sensitivity and specificity and were more sensitive than culture.