Tong M, Xiong Y, Zhu C, et al. - The serum SP-D levels were identified to be closely related to the disease severity in COVID-19 patients in the acute phase, suggesting its possible value as an early potential biomarker of disease severity for stratifying the COVID-19 patients on admission.

• Severe COVID-19 patients showed significantly elevated serum levels of SP-D relative to mild cases (449.7 ± 125.8 vs 245.9 ± 90.0 ng/mL) in the acute phase, while there was a dramatic decrease in the serum levels of SP-D in the recovery period.

• The severe group had considerably higher chest CT imaging scores (median value, 10.0 vs 9.0), while in the recovery period, markedly lower scores were recorded relative to those in the acute phase (median value, 2.0 vs 9.0).

• There was a negative correlation of the SP-D levels with LYM, while a positive correlation was evident with CRP, IL-6, the duration of nucleic acid of the throat swab turning negative, chest CT imaging score on admission and length of stay.

• Risk factors for severe COVID-19 included age and SP-D.