What laboratory finding is commonly associated with adult-onset Still's disease?

Elevated serum ferritin is commonly associated with adult-onset Still's disease, a systemic inflammatory condition characterized by recurrent fevers, rash, and arthritis. This elevated ferritin level reflects the inflammatory nature of the disease and is part of the broader systemic inflammatory response. Ferritin is an acute-phase reactant, meaning its levels rise in response to inflammation, infection, or other stressors. In adult-onset Still's disease, the persistent inflammatory milieu leads to significantly high serum ferritin levels, which can be a useful marker in making the diagnosis.

This laboratory finding can also help differentiate adult-onset Still's disease from other conditions characterized by fever, such as infections or malignancies, where ferritin might not be as markedly elevated. While changes in hemoglobin, lactate dehydrogenase levels, and the erythrocyte sedimentation rate (ESR) may occur in various inflammatory and hematologic conditions, the distinct association between elevated serum ferritin and adult-onset Still's disease is particularly noteworthy and clinically relevant for diagnosis and monitoring of the disease's activity.