Je. Siff et al., Usefulness of the total iron binding capacity in the evaluation and treatment of acute iron overdose, ANN EMERG M, 33(1), 1999, pp. 73-76
The ingestion of iron-containing products is a potential toxicologic emerge
ncy. The total iron binding capacity (TIBC) has been used widely as a predi
ctor of end-organ toxicity and a guide to the need for deferoxamine therapy
. When the TIBC is greater than the serum iron concentration (SIC), it is h
eld that no free iron is present to cause toxicity. The TIBC fails as a mar
ker of toxicity for several reasons. First, the laboratory methods used to
measure TIBC are inaccurate in the setting of iron overload. Second, the pr
esence of deferoxamine, the antidote for iron poisoning, has been shown to
make the TIBC measurement inaccurate. Third, TIBC measurements have been sh
own to be variable. Finally, studies and case reports demonstrate toxicity
even when the TIBC is greater than the SIC. These shortcomings of the TIBC
invalidate it as a predictor of toxicity in iron poisoning.