BALF, bronchoalveolar lavage fluid; CLEIA, AIA‐CL300 based on chemiluminescent enzyme immunoassay; FEIA, AIA‐360 based on fluorescent enzyme immunoassay; ILD, interstitial lung diseases; KL‐6, Krebs von den Lungen‐6. The gene discussed is MUC1; the disease is interstitial lung disease.