Evaluation of the ePlex Respiratory Pathogen Panel 2 to detect viral and bacterial pathogens, including SARS-CoV-2 Omicron in nasopharyngeal swabs

The simultaneous detection and specific identification of multiple pathogens from patients exhibiting respiratory symptoms is important for directing pathogen-specific treatments. The ePlex Respiratory Pathogen Panel 2 (ePlex RP2 panel) is a multiplex molecular test for the qualitative detection of many viral and bacterial pathogens including SARS-CoV-2 in respiratory tract infections. The ePlex RP2 panel received FDA emergency use authorization for nasopharyngeal swab specimens collected in viral transport media. In the evaluation using the ePlex RP2, a total of 67 nasopharyngeal swab specimens were compared to the ePlex RP panel and the CDC 2019-nCoV Real-Time RT-PCR assay as the reference methods. The overall agreement of the ePlex RP2 panel was 100%. The ePlex RP2 panel could detect Omicron BA1 and BA2. The ePlex RP2 panel is a rapid, sensitive and specific "specimen-to-answer" platform to detect simultaneously multiple viruses and bacteria in the upper respiratory tract.

Performance of SARS-CoV-2 antigen testing in symptomatic and asymptomatic adults: a single-center evaluation.

BACKGROUND: Antigen testing offers rapid and inexpensive testing for SARS-CoV-2 but concerns regarding performance, especially sensitivity, remain. Limited data exists for use of antigen testing in asymptomatic patients; thus, performance and reliability of antigen testing remains unclear. METHODS: 148 symptomatic and 144 asymptomatic adults were included. A nasal swab was collected for testing by Quidel Sofia SARS IFA (Sofia) as point of care. A nasopharyngeal swab was also collected and transported to the laboratory for testing by Cepheid Xpert Xpress SARS-CoV-2/Flu/RSV RT-PCR (Cepheid). RESULTS: Overall, Sofia had good agreement with Cepheid (> 95%) in adults, however was less sensitive. Sofia had a sensitivity of 87.8% and 33.3% for symptomatic and asymptomatic patients, respectively. Among symptomatic patients, testing > 5 days post symptom onset resulted in lower sensitivity (82%) when compared with testing within 5 days of symptom onset (90%). Of the four Sofia false-negative results in the asymptomatic cohort, 50% went on to develop COVID-19 disease within 5 days of testing. Specificity in both symptomatic and asymptomatic cohorts was 100%. CONCLUSIONS: Sofia has acceptable performance in symptomatic adults when tested < 5 days of symptom onset. Caution should be taken when testing patients with ≥ 5 days of symptoms. The combination of low prevalence and reduced sensitivity results in relatively poor performance of in asymptomatic patients. NAAT-based diagnostic assays should be considered in when antigen testing is unreliable, particularly in symptomatic patients with > 5 days of symptom onset and asymptomatic patients.