External quality assessment for molecular detection of multiple respiratory pathogens in China

Acute respiratory infections rank the fourth leading cause of mortality globally and impose a substantial burden on public health systems worldwide. Multiplex molecular assays have revolutionized the laboratory diagnosis of acute respiratory infections by enabling simultaneous detection of a broad range of respiratory pathogens. However, variations in nucleic acid extraction and amplification, signal interpretation, and result analysis may impact the consistency of results among laboratories. To systematically evaluate the performance among different laboratories and the comparability among different assays, the first round of an external quality assessment program for the molecular detection of multiple respiratory pathogens was implemented in China.

Each sample panel comprised nine single-infection and three co-infection samples containing various concentrations of inactivated pathogens. The sample panels were coded at random, and the returned results were scored.

Among the 198 participating laboratories, 138 submitted valid datasets; 120 (86.9 %) of these were generated using commercial assays, whereas 18 (13.1 %) were based on laboratory-developed tests. Nine laboratories (6.5 %) achieved competent scores and 112 (81.2 %) exhibited acceptable scores; 17 laboratories (12.3 %) were deemed unqualified, requiring improvement. False results primarily arose from false-negative findings in samples with low pathogen concentrations. In addition, diagnostic performance varied across assays and even among pathogens within the same multiplex assay.

These findings indicate the need for further improvement in accurate detection of multiple respiratory pathogens and emphasized the value for continuous external quality assessment to improve the detection ability of laboratories.