Median values (with lower and upper quartiles) for YKL-40, ALLC, ANC, neutrophil percentage, ALC, lymphocyte percentage, NLR, AEC, eosinophil percentage, AMC, monocyte percentage, ABC, basophil percentage, hemoglobin levels, and hematocrit in patients with severe COPD and patients with very severe COPD are summarized in Table 2. Here, CHI3L1 is linked to chronic obstructive pulmonary disease.