Diagnostic accuracy of point-of-care lung ultrasound for COVID-19: A systematic review and meta-analysis

Matthies, A.; Trauer, M.; Chopra, K.; Jarman, R.

Background. Point-of-care (POC) lung ultrasound (LUS) is widely used in the emergency setting and there is an established evidence base across a range of respiratory diseases, including previous viral epidemics. The necessity for rapid testing combined with the limitations of other diagnostic tests has led to the proposal of various potential roles for LUS during the COVID-19 pandemic. This systematic review and meta-analysis focused specifically on the diagnostic accuracy of LUS in adult patients presenting with suspected COVID-19. Methods. Traditional and grey-literature searches were performed on June 1st 2021. Two authors independently carried out the searches, selected studies and completed the Quality Assessment Tool for Diagnostic Test Accuracy Studies (QUADAS-2). Meta-analysis was carried out using established open-source packages in R. We report overall sensitivity, specificity, positive and negative predictive values and the hierarchical summary receiver operating characteristic curve for LUS. Heterogeneity was determined using the I2 statistic. Results. Twenty studies were included, providing data from a total of 4,314 patients. The prevalence and admission rates were generally high across all studies. Overall LUS was found to be 87.2% sensitive (95% CI 83.6-90.2) and 69.5% specific (95% CI 62.2-72.5) and demonstrated overall positive and negative predictive values of 3.0 (95% 2.3-4.1) and 0.16 (95% 0.12-0.22) respectively. Separate analyses for each reference standard revealed similar sensitivities and specificities for LUS. Heterogeneity between studies was found to be high, and QUADAS-2 assessment identified risks of bias in many studies. Conclusion. During a period of high prevalence, LUS is a highly sensitive diagnostic test for COVID-19. However, more research is required to confirm these results in more generalisable populations, including those less likely to be admitted to hospital.