Abnormal carbon monoxide diffusion capacity in COVID-19 patients at time of hospital discharge

I have read with great interest the article by M o et al . [1] entitled “Abnormal pulmonary function in COVID-19 patients at time of hospital discharge” recently published in the European Respiratory Journal . In this study, the authors describe pulmonary function tests in patients who suffered from coronavirus disease 2019 (COVID-19), which were performed on discharge from hospital. Patients were classified into three groups of severity. In the patients who suffered more severely, measured carbon monoxide diffusion capacity ( D LCO ) was lower. However, when looking at D LCO / V A , which represents the transfer factor of carbon monoxide, the picture is different. Patients who had severe pneumonia had an average D LCO / V A of 82% of predicted while patients in groups classified as having mild disease or pneumonia had average values above 90%. Notably, all these averages have relatively high standard deviation values ( e.g. 13.9% in severe pneumonia), meaning that some patients in the post-severe pneumonia group had a D LCO / V A >90% of predicted. On recovery from COVID-19 it is important to draw attention to the CO diffusion test and the actual meaning of the findings when considering the values of D LCO and D LCO / V A put together https://bit.ly/36k2O2Q