Reference values of serum transferrin receptor (sTfR) and sTfR/log ferritin index in healthy children

ABSTARCT

The aims of this study were to determine appropriate reference ranges for serum transferrin receptor (sTfR) and sTfR/log ferritin (sTfR-F index) in healthy children and their relationship with iron parameters, erythropoiesis, and other conditions presented by the subject. A total of 902 children with normal iron status, aged 1–11 years, were included in a cross-sectional study. A physical examination was conducted and z-score of body mass index (zBMI) obtained. Complete blood count, iron biomarkers, erythropoietin, C-reactive protein, sTfR, and sTfR/log ferritin were determined. Linear multiple regression was applied to identify the factors that determined sTfR and sTfR-F index variability. Mean values for sTfR and sTfR-F index were 1.22 ± 0.28 mg/L (95% confidence interval [CI]: 1.2–1.23) and 0.87 ± 0.25 (95% CI: 0.85–0.88). The reference intervals (2.5th to 97.5th percentiles [P_2.5–P_97.5]) were 0.78–1.9 mg/L and 0.49–1.46, respectively. sTfR and sTfR-F values decreased with age (P <.03 and P <.0001, respectively). No changes were observed with sex. Changes in sTfR and sTfR-F index were consistent with ferritin and erythropoietin variations. Iron biomarkers, erythropoietin, and zBMI predicted 19% and 18.1% of the sTfR and sTfR-F index variability. The results provide reference ranges for sTfR and sTfR-F index in healthy children for clinical use in the assessment of body iron status. Both biomarkers are predicted by iron parameters, erythropoietin, and zBMI.

KEYWORDS:

• Healthy children
• iron deficiency
• serum erythropoietin
• serum transferrin receptor
• serum transferrin receptor/log ferritin index

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.