Molecular diagnostic for SARS-CoV-2: An experimental external quality assessment scheme

ABSTRACT

Background: External Quality Assessment (EQA) is a valuable tool to monitor and improve the analytical performances of clinical laboratories. During the COVID-19 pandemic, the number of kits to detect the infection and the number of tested samples intensified to satisfy the test request. To guarantee suitable results, EQA scheme providers have implemented specific schemes assessing different SARS-CoV-2 diagnostic systems. This study aims to describe the results collected in an experimental EQA scheme for molecular diagnostic of SARS-CoV-2 managed by INSTAND e.V with the collaboration of the Centre of Biomedical Research for Quality in Laboratory Medicine for Veneto Region Laboratories. Methods: The qualitative EQA results collected, two surveys in 2020 and one in 2021, for 18 samples total, have been summarized to identify the percentage of laboratory results per sample. Control samples included SARS-CoV-2 or other seasonal coronaviruses (MERSCoV, HCoV 229E, HCoV OC43) provided by Nationales Konsiliarlaboratorium fur Coronaviren of Berlin. SARSCoV-2 Variants of Concern (VOCs) were included only in the 2021 survey. Results: The average of the participating laboratories strongly decreased between the first survey of 2020 (927) and the last analysed survey, March 2021 (594). The main analytical procedures used, in the first, second and third survey respectively were CEPHAID kits (11.6%, 12% and 11.7%), in-house produced assays (10.4, 6.2 and 5%), SEEGENE kits (8.5%, 8.1% and 7.9%), ROCHE Diagnostics (8.3%, 8.5% and 6.9%) and ALTONA Diagnostics kits (6.1, 6.2 and 4.5%). A good agreement was found among laboratories results, with an overall range from 95% to 99.8%. Furthermore, generally from 0.2% to 2.9% of incorrect results and 0% to 1.1% of indeterminate results were reported. Conclusions: The EQA programs are a fundamental quality assurance tool to evaluate the laboratory performance and know the State-of-the-Art diagnostic systems used by participating laboratories. The need for an EQA scheme for every test performed in the laboratory is mandatory to guarantee patient safety.