Background: COVID-19 pneumonia causes alveolar-capillary membrane damage. Time of lung membrane repair after COVID-19 is still unknown.

Aim. To investigate the degree of DLCO changes after COVID-19 pneumonia.

 Materials and methods. Clinical data, DLCO were assessed in 39 patients (pts) in acute phase of COVID-19. According to severity 1st group included 14 pts (36%) with moderate course of COVID-19, 2nd group ? 19 pts (49%) with severe, 3rd group ? 6 pts ­(15%) with critical. They were investigated at 45 (40; 60) day from COVID-19 first symptoms. Non-parametrical statistical methods were used.

Results. Results of DLCO lever presented in table 1 and fig.1. None of groups had normal DLCO. 

In 1st group 9(64,0%) pts had impaired DLCO, in 2nd ?17(89,5%) pts, whereas in 3rd ? all 6 (100%) pts. There was a moderate negative relationship between DLCO and the severity of lung damage (r=-0,57, ?<0,01).

Conclusions. Diffusion lungs capacity stays impaired at 45(40;60) day from COVID-19 in vast majority of cases. DLCO varies from slight decrease observed in case of moderate course to moderate decrease after critical course of COVID-19.