Objective To investigate the diagnostic value of
serum ferritin in
children with systemic onset
juvenile idiopathic arthritis (SO-JIA).
Methods Fifty-seven
patients with
fever of unknown origin (rectal
temperature>38.5 ℃ ) over two weeks and hospitalized in our general
medicine ward longer than one week were enrolled in this study.
Patients were recorded the
course of
fever, elinieal
symptoms and signs including
rash and swollen
joints/
arthralgia,
laboratory tests including complete
blood cell count,
C-reactive protein, erythroeyte
sedimentation rate,
lactate dehydrogenase and the level of
serum ferritin. SPSS 10.0 was used for
statistical analysis. Results Two of 57
patients could not be diagnosed before discharge. The other 55
patients whose
diagnosis was confirmed were divided into four groups. Twenty-five
patients were SO-JIA,12
patients had hematologic or oncological
diseases, 12
patients had
infectious diseases and 6
patients had other
rheumatic diseases. The level of
serum ferritin was significantly higher (P<0.01) in SO-JIA group than in other groups. Moreover, the levels of
serum ferritin in SO-JIA group were all higher than normal and the levels of
serum ferritin in 76% of SO-JIA group were more than five-fold elevation. Four cut-off levels of
serum ferritin level for the
diagnosis of SO-JIA were selected based on clinical practice and
ROC curve. When the cut-off levels of
serum ferritin were 328.25, 529.50, 731.05 ng/ml and 1121.10 ng/ml, the
sensitivity for the
diagnosis were 100%, 88%, 72%, and 64% respectively, the
specificity were 77%, 87%, 90% and 100%,respectively. Conclusion
Serum ferritin is valuable for the
diagnosis of SO-JIA and 529.50 ng/ml may be a good cut-off level