The Lavin-Osband Scale classifies LCH into four types (grades) based on age, number of affected organs, and presence of organ function impairment. The higher the score, the worse the prognosis, simplifying diagnosis and aiding in prognosis assessment and treatment guidance.

Organ function impairment mainly refers to damage to liver, lung, and bone marrow hematopoietic function.

Liver function impairment: Presence of one or more of the following abnormalities: ① Hypoproteinemia: total protein <55g/L or albumin <25g/L; ② Bilirubin >25.7μmol/L (1.5mg/dL); ③ Edema or ascites.

Respiratory function impairment: Presence of one or more of the following symptoms without infection: dyspnea, cyanosis, pleural effusion, or pneumothorax.

Bone marrow hematopoietic function impairment: Presence of one or more of the following abnormalities: ① Hemoglobin <100g/L (excluding iron deficiency anemia); ② White blood cells <4×10^9/L or absolute neutrophil count <1.5×10^9/L; ③ Platelets <100×10^9/L.