Variable sensitivity in molecular detection of SARS-CoV-2 in European Expert Laboratories: External Quality Assessment, June - July 2020

Objective: During the ongoing coronavirus disease 2019 (COVID-19) outbreak, robust detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a key element for clinical management and to interrupt transmission chains. We organized an external quality assessment (EQA) of molecular detection of SARS-CoV-2 for European expert laboratories.Study design: An EQA panel composed of 12 samples, containing either SARS-CoV-2 at different concentrations to evaluate sensitivity or other respiratory viruses to evaluate specificity of SARS-CoV-2 testing, was distributed to 68 laboratories in 35 countries. Specificity samples included seasonal human coronaviruses hCoV-229E, hCoV-NL63 and hCoV-OC43, as well as MERS-CoV, SARS-CoV and human influenza virus A and B.Conclusion: Sensitivity was variable among laboratories, particularly for low concentration SARS-CoV-2 samples. Results indicated that performance was mostly independent of the selection of specific extraction or PCR methods. EQA participants: Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institute, Germany et al.