Neutrophil Gelatinase-Associated Lipocalin (NGAL) as a Biomarker of Iron Deficiency in Hemodialysis Patients

Iron deficiency is often present in Hemodialysis (HD) patients. NGAL is a novel regulator of iron related gene that may contribute to anemia in HD patients. We conducted this study to evaluate the relationship of NGAL and the iron status in HD patients. Prospective cohort study was carried out, in between Dec 2012 to Mar 2014. The total number of the study was 120 hemodialysis patients among them 67 males and 53 females. According to transferrin saturation (TSAT) the eligible participants were divided into two equal subgroups. Group IA: TSAT <20% (iron deficiency). Group IB: TSAT = 20% (without iron deficiency). Additional 60 healthy volunteers as control group (Group II). NGAL levels, indices of anemia, such as ferritin, TSAT and serum iron were measured in all subjects. NGAL level was significantly higher in HD patients than the healthy control group; furthermore, HD patients with TSAT < 20 had lower NGAL values than HD patients with TSAT = 20. Surprisingly NGAL values significantly increased to comparable level after correction of iron deficiency by i.v. iron administration. The mean value of S. iron, S. transferrin, TSAT and S. ferritin were significantly higher in group IB than group IA. NGAL cutoff level of =461 ng/ml had a greater sensitivity and specificity than ferritin level of <200 ng/ml and TSAT level of < 20% in identifying iron deficiency among HD patients. All study parameters were correlated with NGAL level: Only SCr (P<0.05), ALP (P<0.01), HB (P<0.001), hsCRP (P=<0.001), S. Iron (P<0.001), TSAT (P<0.001) and ferritin (P<0.001) were positively correlated with NGAL level. The potential use of NGAL measurement may be valuable as a novel marker of iron status among hemodialysis patients.