Head-to-head comparison of the performance of BIOFIRE® SPOTFIRE® Respiratory/Sore Throat Panel, Cepheid Xpert® Xpress SARS-CoV-2/Flu/RSV and Cobas® SARS-CoV-2 & Influenza A/B assay for detection of respiratory viruses.

BACKGROUND

We compared the performance of 3 multiplex respiratory platforms - BIOFIRE® SPOTFIRE® Respiratory/Sore Throat (R/ST) Panel (BioMérieux), Xpert® Xpress SARS-CoV-2/Flu/RSV assay (Cepheid) and Cobas® SARS-CoV-2 & Influenza A/B assay (Roche) to detect Flu A/ B, SARS CoV-2 and RSV from nasopharyngeal swabs (NPS).

METHOD: A total of 250 leftover pediatric NPS from routine clinical testing (50 positives for each target and 50 negatives) were tested on all 3 platforms. Results were compared to a composite reference standard to calculate positive percent agreement (PPA) and negative percent agreement (NPA). For RSV, PPA and NPA were calculated by comparing Xpress and SPOTFIRE assays only. Discrepant samples were tested by single-plex PCRs for each viral target.

RESULTS

PPA ranged between 97 % and 100 % for all targets except SARS-CoV-2 (86-97 %); NPA was > 95 % by all assays. SPOTFIRE reported 35 (14 %) discrepant samples, Xpress and Liat reported 31 (12.4 %) and 14 (5.6 %) samples respectively. SPOTFIRE was positive for an additional respiratory virus (excluding Flu A/B, SARS-CoV-2 and RSV) in 110/250 (44 %) samples. All samples with initial invalid results on Xpress (5, 2 %), SPOTFIRE (3, 1.2 %) and Liat (2, 0.8 %) were valid on re-testing. Total hands-on time (specimen processing and loading, retrieving results) was less than 5 min for all assays.

CONCLUSION

All 3 assays showed 95 % agreement for Flu A and B detection; performance for SARS-CoV-2 detection varied. SPOTFIRE provides an advantage of detecting additional respiratory pathogens. Overall, the assays were easy to perform with minimum technical skill.