The diagnosis of adult-onset Still's disease currently requires application of Yamaguchi's criteria and then exclusion of infectious, hematologic, autoimmune and neoplastic disorders. A recent article suggests that very high levels of serum ferritin together with an unusually low percentage of glycosylated ferritin may serve as diagnostic criteria or even as markers of disease progression. This new score has greater specificity than the other scores, including that of Yamaguchi.
We describe 3 new cases with very high ferritin levels (exceeding 9000 microg/L) and glycosylated ferritin levels lower than 20%.
The diagnosis of Still's disease was determined in all three cases by both Yamaguchi's score and the new criteria. One patient responded well to treatment with colchicine.
Ferritin and glycosylated ferritin levels are interesting diagnostic markers. The new score suggested by Fautrel et al. is especially useful in that it does not require the exclusion of a list of differential diagnoses.