Serum soluble transferrin receptor concentrations in US preschool children and non‐pregnant women of childbearing age from the National Health and Nutrition Examination Survey 2003–2008

Abstract

Serum soluble transferrin receptor (sTfR) is elevated during increased cellular iron demands and erythropoiesis. It is recommended as a sensitive and accurate measure of iron deficiency in populations. The lack of assay standardization and of representative data on the distribution of sTfR in at‐risk populations limits its use. Using data from NHANES 2003–2008, we examined the distribution of sTfR and developed assay‐specific cutoff values for defining elevated sTfR in two US populations groups: children 1–5 y (n=2042) and non‐pregnant women 12–49 y (n=5656). On average, children had higher geometric mean sTfR concentrations (4.20 mg/L; CI: 4.15–4.26) than non‐pregnant women (3.42 mg/L; CI: 3.37–3.48) (p<0.001). Among children, those aged 1–2 y (compared to those aged 3–5 y), boys (compared to girls), and non‐Hispanic black [NHB] children (compared to non‐Hispanic white [NHW] and Mexican‐American [MA] children) had higher sTfR concentrations. Among non‐pregnant women, adolescents (12–19 y) had higher sTfR concentrations than adults aged 20–34 y but not compared to adults aged 35–49 y; NHB women (compared to NHW and MA women) and multiparous women (compared to nulliparous women) had higher sTfR concentrations. The derived cutoff values (95th percentile in a defined healthy reference population) for elevated sTfR in the US were 5.74 mg/L for children 1–5 y and 4.94 mg/L for non‐pregnant women 12–49 y.