Abstract
Background The currently available various methods of estimation of total iron binding capacity
(TIBC) show marked variation in reference range. Although serum transferrin (TF) level
is a sensitive indicator of iron status, its measurement requires immunoassay equipment
which may not be available in many routine biochemistry laboratories. So, this study
was planned to find the most appropriate method to estimate TIBC.
Objectives This study aimed to compare different methods of TIBC estimation and to corelate
the TIBC values obtained by different methods with serum TF concentration.
Material and Methods This analytical cross-sectional study was performed in the clinical chemistry laboratory
of the Biochemistry Department of Medical College Baroda & SSG Hospital, Vadodara,
Gujarat, on 250 leftover serum samples destined to be discarded. In all these samples,
serum TIBC was estimated by direct method, indirect method, as well as calculated
method (iron + unsaturated iron binding capacity [UIBC]) along with the measurement
of serum TF level.
Statistical Analysis Among the different methods, repeated analysis of variance (ANOVA) analysis and Bland–Altman
plot were used to find out significance of difference. Correlation coefficients were
found between different methods of TIBC estimation and serum TF levels.
Results The means of TIBC by calculated, indirect, and direct methods were 344.51, 342.23,
and 378.24 µg/dL, respectively. The mean of serum TF was 295.3 mg/dL. There was statistically
significant difference between TIBC by direct and indirect methods and between direct
and calculated methods. There was a strong positive correlation between TIBC by direct
method and serum TF (r = 0.888, p < 0.0001), but there was moderate correlation between TIBC by indirect method and
serum TF (r = 0.748, p < 0.04), and between TIBC by calculated method and serum TF (r = 0.725, p < 0.05).
Conclusion Among different methods of estimation of TIBC, direct method is more reliable in
reference to serum TF levels.
Keywords
TIBC - serum transferrin - iron status
