Fh. Wians et al., Soluble transferrin receptor (sTfR) concentration quantified using two sTfR kits: analytical and clinical performance characteristics, CLIN CHIM A, 303(1-2), 2001, pp. 75-81
We compared the analytical and clinical performance characteristics of the
Rameo and R&D Systems enzyme-linked immunosorbent assays (ELISAs) for quant
ifying serum levels of soluble transferrin receptor (sTfR). In addition, we
determined both the number of samples required to determine the true indiv
idual mean sTfR concentration for a single individual and the critical diff
erence (CD) between serial measurements that indicates a statistically sign
ificant change in sTfR concentration, sTfR concentration was determined in
127 serum samples selected retrospectively from males (n=32) and non-pregna
nt (n=40) and pregnant women (n=55). Intra- and inter-assay precision for b
oth methods was good (CV values 5-10%) to excellent (CV values <5%) over a
wide range of sTfR concentrations. Correlation between these methods was go
od (r=0.93); however, sTfR values by the R&D hit were <similar to>2.9 times
higher than values obtained using the Rameo hit on the same serum samples.
Nevertheless, receiver-operator characteristic (ROC) curve analysis demons
trated that the diagnostic accuracy of both assays in discriminating betwee
n patients with iron-deficiency anemia (IDA) or anemia of chronic disease (
ACD) was high (area-under-the-curve (AUC) values >0.95) and not significant
ly different (P=0.480). We determined that a minimum of 8 samples are requi
red to determine an individual's true sTfR concentration, while a >40% diff
erence between serial sTfR measurements would he required to indicate a sta
tistically significant change in sTfR concentration. We concluded that both
the Rameo and R&D Systems sTfR methods have similar analytical and clinica
l performance characteristics and were likely to be equally useful in discr
iminating between patients with biochemically defined IDA ol ACD. (C) 2001
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