Serum ferritin in juvenile chronic polyarthritis.

Six children with juvenile chronic polyarthritis were studied and their disease activity correlated with haematological values including serum ferritin. The latter is often raised above reference values, but even when within them appears to fluctuate significantly and correlates more closely with disease activity than any of the other parameters measured. We conclude that the serial measurement of serum ferritin may be a useful guide to the management of such children.