Disparity of serum transferrin receptor measurements among different assay methods

Abstract

Objective: To highlight differences in the quantification of transferrin receptor (TfR) concentration (a reliable index of iron deficiency) between three different assay methods.

Design: Methods comparison of TfR measurements in ‘elevated’ and ‘normal’ human sera using the Ramco, Quantikine and ‘Lab’ assays.

Setting: The Hospital for Sick Children, Toronto, Ontario, Canada.

Subjects: Pooled TfR for elevated and normal human sera obtained from the Ramco TfR assay kit.

Main outcome measures: Differences between TfR concentrations in normal and elevated samples and repeatability for each assay method and limits of agreement in TfR quantification between assay methods.

Results: The mean TfR concentrations for the elevated reference serum samples was higher than the normal reference samples within each individual assay (P<0.001); however, measurement agreement between methods was poor.

Conclusions: Recognition of the relative differences in the values obtained from each of the assays should affect the interpretation of TfR concentration as an index of iron deficiency.

Sponsorship: This research was supported by the Ministry of Agriculture, Food and Rural Affairs Ontario.