Utility of new red cell parameters for distinguishing functional iron deficiency from absolute iron deficiency in children with familial Mediterranean fever.

ABSTRACT

INTRODUCTION: Few data are available on the clinical utility of new red cell parameters for detecting anemia in children with inflammatory diseases. The aim was to investigate the utility of three new red cell parameters for distinguishing functional iron deficiency (FID) from absolute iron deficiency (AID) in children with familial Mediterranean fever (FMF). METHODS: The study involved 198 children with genetically confirmed FMF and 18 healthy-age and sex-matched controls. Complete blood counts with the new red cell parameters of low hemoglobin (Hb) density (LHD), microcytic anemia factor (MAF), and red blood cell size factor (RSF) were measured in a Unicel® DxH800, along with conventional iron parameters. The FMF patients' medical records were retrospectively reviewed to assess inflammation status and genetic results. RESULTS: The frequencies of FID and AID among the 198 FMF patients were 35% and 65%, respectively. Among patients with homozygous MEFV mutation, FID was more common than AID (P < 0.05). Mean LHD was significantly higher and mean Hb, MCV, MAF, and RSF were significantly lower among the FMF patients with FID compared to those with AID and controls (P < 0.05). Specificity for distinguishing FID from AID in children with FMF was greatest for MAF (92%; 95% confidence interval [CI] 85%-96%), followed by LHD (85%; 95% CI 76%-91%) and RSF (81%; 95% CI 72%-88%). CONCLUSION: The new red cell parameters measured by the Unicel® DxH800 may be useful for guiding physicians in distinguishing FID from AID in children with FMF.