Evaluation of alternative clinical samples for the detection of SARS-CoV-2 and influenza virus by automated multiplex RT-PCR.

Introduction: The aim of this study was to compare the performance of different clinical specimens-nasopharyngeal (NP) swabs collected by healthcare professionals (HCP-NP), self-collected nasal swabs (Sc-N), and saliva samples (S)-in diagnostic tests for investigating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and influenza A/B RNA.

Methodology: These clinical samples were collected from 404 symptomatic cases and tested with the SARS-CoV-2 and influenza A/B RNA tests on the cobas 6800 System of Roche Molecular Systems (Roche Molecular Systems, Pleasanton, USA). The SARS-CoV-2 or influenza virus infection status was determined for all patients based on the predefined criteria and corresponding algorithms. Positive and negative predictive values (PPV, NPV), sensitivity, specificity, coefficient of variation (CV), interrater reliability, correlation, ,and days of sample collection of these three sample types were analyzed.

Results: There was almost perfect agreement between the these sample types for the diagnosis of SARS-CoV-2 and influenza A. The overall performance (PPV, NPV, sensitivity) and reproducibility (CV ≤ 6%) were favorable. Additionally, they showed similar trends for days of sample collection.

Conclusions: Diagnostic detection of SARS-CoV-2 and influenza RNA from Sc-N and S samples was comparable to HCP-NP samples. Using these samples would provide an advantage in diagnosing SARS-CoV-2 and influenza A infection, as they can be easily collected without the need for viral transport media.