The threshold value of progranulin for the differentiation between COVID-19 and non-COVID-19 pneumonia yielded a sensitivity of 0.91 (95% CI = 0.71–0.99) at a specificity of 0.94 (95% CI = 0.79–0.99) with a positive likelihood ratio (LR+) of 14.09, a negative LR− of 0.10, a positive predictive value (PV+) of 0.91 and negative PV− of 0.93. Here, GRN is linked to COVID-19.