Determination of reference values for the soluble transferrin receptor (sTfR) on a cross sectional population sample.

Background. Aim of the study was to determine reference values for the soluble Transferrin Receptor (sTfR) in a cross sectional population sample. Methods: For the determination of reference values, using a standard calibrated fluorescence-immunoassay, the samples (990 females; 1060 males; 13 - 65 years old) were divided into five groups according to age and sex. Soluble transferrin receptor and ferritin were measured by a fluorescence-immunoassay with AIA-21 (TOSOH BIOSCIENCE, Tessenderlo, Belgium). The sTfR/logFer-Index was calculated by dividing the sTfR by the logarithm of ferritin, the logsTfR/Fer-Index by dividing the logarithm of sTfR by ferritin. Results: Mean sTfR concentration was 1.75 +/- 0.39 mg/l in group I (13-17 years), 1.65 +/- 0.34 mg/l in group II (18-30 years), 1.60 +/- 0.39 mg/l in group III (31-40 years), 1.54 +/- 0.39 mg/l in group IV (41-50 years), and 1.59 +/- 0.34 mg/l in group V (51-65 years), respectively. A gender-specific difference between the groups was observed: sTfR concentrations were lower in group I (p<0.005) and group II (p=0.01) for women. The mean sTfR-concentration decreased consecutively in the age group I-IV (13-50 years). Conclusions: This is the first cross sectional population based study to determine reference values for sTfR-concentrations. Our results demonstrated age- and gender-specific differences. (Clin. Lab. 2009;55:193-199)