Evaluation of a fully closed real time PCR platform for the detection of SARS-CoV-2 in nasopharyngeal swabs: a pilot study.

AIMS: To date, reverse transcriptase PCR (RT-PCR) on nasopharyngeal swabs is the 'gold standard' approach for the diagnosis of COVID-19. The need to develop easy to use, rapid, robust and with minimal hands-on time approaches are warranted. In this setting, the Idylla SARS-CoV-2 Test may be a valuable option. The aim of our study is to evaluate the analytical and clinical performance of this assay on previously tested SARS-CoV-2 people by conventional RT-PCR based approach in different settings, including initial diagnosis and clinical follow-up.

METHODS

To evaluate the sensitivity and specificity of the Idylla SARS-CoV-2 Test, we retrieved 55 nasopharyngeal swabs, previously analysed by a fully validated assay, from symptomatic patients or from people who have been in close contact with COVID-19 positive cases. Discordant or high discrepant cases were further analysed by a third technique. In addition, a second subset of 14 nasopharyngeal swab samples with uncertain results (cycle threshold between 37 and 40), by using the fully validated assay, from patients with viral infection beyond day 21, were retrieved.

RESULTS

Overall, Idylla showed a sensitivity of 93.9% and a specificity of 100.0%. In addition, in the additional 14 nasopharyngeal swab samples, only five (35.7%) featured a positive result by the Idylla SARS-CoV-2 Test.

CONCLUSIONS

We demonstrated that the Idylla SARS-CoV-2 Test may represent a valid, fast, highly sensitive and specific RT-PCR test for the identification of SARS-CoV-2 infection.