External quality assessment for nucleic acid test of the novel coronavirus

ABSTRACT

Objective: To evaluate the performance of laboratories for nucleic acid test of the novel coronavirus in China by external quality assessment (EQA). Methods: The specially -treated virus RNA, extracted from cultured novel coronavirus, was used as EQA samples. The inactivated clinical samples of influenza A virus, influenza B virus, and respiratory syncytial virus were used as negative samples. Then, the applicability, homogeneity and stability of the EQA samples were evaluated. The panels consisted of 6 coded samples (ungrouped in the first round/second grouped in the second round) were distributed to participants by cold chain express delivery and the testing information and results were summarized and evaluated. Results: The EQA samples are suitable for the mainstream nucleic acid test reagents on the market. Homogeneity and stability meet the requirements of the China National Accreditation Service for conformity Assessment. For the first-round and the second-round, 243 and 60 valid lab results were submitted respectively. The laboratories with completely correct results were 98.8% (240/243) and 73.3% (44/60), and those with unqualified results were 1.2% (3/243) and 26.7% (16/60). The overall coincidence rate of the first and second samples was 99.8% (1455/1458) and 94.7% (341/360), respectively. The false-positive rates were 0.1% (1/729) and 2.5% (3/120), and the false-negative rates were 0.3% (2/729) and 6.7% (16/240). Conclusion: Participating Laboratories have a good overall ability to test the new coronavirus nucleic acid, and the false negative results are the main problem affecting the accuracy of testing. Before routine use of related reagents, laboratories should verify and compare the performance of reagents from different manufacturers.