De Barun K, Roberts William L
Department of Pathology, University of Mississippi Medical Center, Jackson, MS, USA.
Clin Chim Acta. 2003 Jul 1;333(1):51-7. doi: 10.1016/s0009-8981(03)00169-4.
Measurements of serum iron and total iron-binding capacity (TIBC) can be used to aid the diagnosis of iron deficiency and iron overload states. A variety of different methods for these measurements are commercially available.
Linearity, imprecision and hemoglobin interference of homogeneous iron and TIBC methods on a Dimension RxL analyzer were assessed. Method comparison studies were performed with a Vitros 950 analyzer.
The Dimension RxL iron method was linear from 40 to 1000 microg/dl. The coefficient of variation of the iron and TIBC methods were <4% and <2%, respectively, at iron concentrations of 68 and 228 microg/dl and TIBC concentrations of 206 and 384 microg/dl. Comparison of the Vitros 950 and Dimension RxL iron methods gave a slope of 0.97, an intercept of 6.0 and r=0.99. Corresponding results for the TIBC methods were 1.02, -6.6 and r=0.97, respectively. Simulation of acute iron overload in vitro did not produce the same effect on TIBC measurements as in vivo overload. Iron recovery by the Dimension RxL method was reduced 40-60% by the addition of deferoxamine at a concentration of 200 micromol/l.
The Dimension RxL assay provides acceptable measurements of iron and TIBC in routine patient samples. Iron measurements are unreliable in the presence of deferoxamine.
