Plasma Hepcidin Levels in Healthy Children: Review of Current Literature Highlights Limited Studies.

BACKGROUND: There are few studies that highlight pediatric hepcidin reference ranges especially from Asian subcontinent. In current study, plasma from 131 children (72 boys and 59 girls; 1 to 12 y) was analyzed for hepcidin-25 by enzyme-linked immunosorbent assay. OBSERVATIONS: The median (interquartile range) plasma hepcidin in boys was 21.89 ng/mL (16.50 to 51.70 ng/mL) and girls was 21.95 ng/mL (19.20 to 47.70 ng/mL). No statistically significant difference (P=0.937) of plasma hepcidin levels in sex was noted. However, multiple regression analysis revealed a significant correlation between plasma hepcidin levels and ferritin (P=0.000). CONCLUSIONS: Our study results highlight relatively lower median hepcidin values in children 1 to 12 years of age as compared with western data. This may be attributed to either lack of a harmonized and standard enzyme-linked immunosorbent assay detection methodology or to presence of clinically significant polymorphisms in hepcidin gene in our population.

Provisional standardization of hepcidin assays: creating a traceability chain with a primary reference material, candidate reference method and a commutable secondary reference material.

Background Hepcidin concentrations measured by various methods differ considerably, complicating interpretation. Here, a previously identified plasma-based candidate secondary reference material (csRM) was modified into a serum-based two-leveled sRM. We validated its functionality to increase the equivalence between methods for international standardization. Methods We applied technical procedures developed by the International Consortium for Harmonization of Clinical Laboratory Results. The sRM, consisting of lyophilized serum with cryolyoprotectant, appeared commutable among nine different measurement procedures using 16 native human serum samples in a first round robin (RR1). Harmonization potential of the sRM was simulated in RR1 and evaluated in practice in RR2 among 11 measurement procedures using three native human plasma samples. Comprehensive purity analysis of a candidate primary RM (cpRM) was performed by state of the art procedures. The sRM was value assigned with an isotope dilution mass spectrometry-based candidate reference method calibrated using the certified pRM. Results The inter-assay CV without harmonization was 42.1% and 52.8% in RR1 and RR2, respectively. In RR1, simulation of harmonization with sRM resulted in an inter-assay CV of 11.0%, whereas in RR2 calibration with the material resulted in an inter-assay CV of 19.1%. Both the sRM and pRM passed international homogeneity criteria and showed long-term stability. We assigned values to the low (0.95±0.11 nmol/L) and middle concentration (3.75±0.17 nmol/L) calibrators of the sRM. Conclusions Standardization of hepcidin is possible with our sRM, which value is assigned by a pRM. We propose the implementation of this material as an international calibrator for hepcidin.