Abstract
Maes M, Bosmans E, Scharpé S, Hendriks D, Cooremans W, Neels H, De Meyer F, D'Hondt P, Peeters D. Components of biological variation in serum soluble transferrin receptor: relationships to serum iron, transferrin and ferritin concentrations, and immune and haematological variables. Scand J Clin Lab Invest 1997:57:31–41.
We investigated the components of biological variation in serum soluble transferrin receptor (TfR) in relation to serum iron, transferrin (Tf), ferritin, soluble interleukin-2 receptor (sIL-2R), sIL-6R, and number of erythrocytes, haemoglobin (Hb), haematocrit (Ht), mean corpuscular volume (MCV), mean cell haemoglobin (MCH), and erythrocyte distribution width (RDW). We took monthly blood samples during 1 calendar year from 26 healthy subjects for assay of the above variables. The estimated CVs for TfR were interindividual CVg=20.8%, and intra-individual CVi=13.6%; for Tf, CVg=14.4% and CVi=6.7%; for iron, CVg=16.8% and CVi=29.2%; and for ferritin, CVg=71.1% and CVi=26.5%. There was a statistically significant seasonal pattern in the four variables with significant annual, biannual and/or trimonthly rhythms, which were expressed as a group phenomenon. The peak-trough differences in the yearly variations, expressed as a percentage of the mean, were: for TfR, 11.7%; for iron, 39.2%; for Tf, 11.7%; and for ferritin, 29.3%. Up to 34.2% of the within-subject variability in TfR (which reflects changes over time) could be explained by the regression on iron, ferritin, Tf, sIL-2R, sIL-6R and MCH values. Up to 67.2% of the between-subject variability in TfR (which reflects differences in the homeostatic setpoint during the study year) could be explained by the regression on gender, iron, Tf, and ferritin values.