Is it Possible to Use Monocyte Distribution Width (MDW) as a Diagnostic Parameter for COVID-19 in the Emergency Department?

Background: COVID-19 has been shown to cause an overactivation of monocytes. The Monocyte Distribution Width (MDW) parameter correlates with the cytomorphological changes that monocytes undergo after their massive activation. MDW is obtained from the blood count, and it could be established as a potential diagnostic biomarker for COVID-19. Therefore, the aim of this study is to deeply analyze the value of MDW in patients with SARS-CoV-2 infection. Materials and Methods: A total of 4,153 patients treated in the Emergency Department with suspicion of SARS-CoV-2 infection due to suggestive symptoms were recruited. A blood count and a nasopharyngeal swab for SARS-CoV-2 RNA detection were requested. Results: Significant differences (p<0.001) were observed between the MDW values in patients with COVID-19 (n =1285), with a mean and standard deviation of 23.69 ± 4.27 compared to patients without COVID-19 disease (n = 2870) whose mean and standard deviation is 19.17 ± 3.52. The Area Under the Curve (AUC) obtained was 0.822 and the cut-off point was MDW≥20.8, (77.7% sensitivity, 78.1% specificity). The combination of MDW with White Blood Count (WBC) through a regression model got the best AUC (AUC=0.855), with a sensitivity of 79.2% and a specificity of 83.7%. Conclusion: Patients with SARS-CoV-2 infection have been shown to have higher MDW values. The combination of MDW with WBC allowed to obtain the highest specificity from all the studies performed, so this combination could be helpful when classifying patients with possible COVID-19. Both markers are obtained very quickly and easily from a blood count sample.