The Simplexa(tm) Group A Strep Direct Assay: a sample to answer molecular assay for the diagnosis of group A streptococcal pharyngitis
ABSTRACT The Simplexa(tm) Group A Strep Direct assay is intended for use on the Integrated Cycler for detection of Group A Streptococcus (GAS) directly from throat swabs that have not undergone nucleic acid extraction. A prospective study of 1352 samples in 4 geographically diverse sites showed an overall prevalence of GAS of 15.4% The assay demonstrated 97.4% sensitivity and 95.2% specificity versus culture. The positive predictive value compared to culture was 72.7% However, 46 out of 57 discrepant samples were Group A Strep positive when tested using a bi directional sequencing method illustrating the increased sensitivity of the assay compared to culture for detection of GAS. Rapid and accurate diagnosis of GAS allows for timely treatment to decrease complications of this prevalent organism that continues to cause substantial morbidity and mortality worldwide.
Expert review of molecular diagnostics