REASSESSMENT OF MEASURING TOTAL IRON-BINDING-CAPACITY IN ACUTE IRON OVERDOSE

OBJECTIVE: To evaluate recent data that suggest that total iron bindin g capacity (TIBC) is not a reliable laboratory parameter in assessing acute iron overdose. DATA SOURCES: A MEDLINE search of the literature with a fan search of relevant articles. STUDY SELECTION AND DATA EXTRA CTION: Laboratory, human, and animal studies on die measurement and re levance of TIBC in acute iron poisoning were reviewed. These data were analyzed in light of the current guidelines for use of TIBC in assess ing iron poisoning. DATA SYNTHESIS: There are significant data to sugg est that the sensitivity of TIBC in acute iron poisoning is unacceptab le. This lack of sensitivity is also reflected in the poor positive pr edictive value of TIBC. The specificity and negative predictive value are higher but not without error. One survey of 500 laboratories repor ted a coefficient of variation for TIBC of 16 percent (95 percent conf idence interval), suggesting unacceptable accuracy. CONCLUSIONS: These data suggest that TIBC may not be a reliable laboratory parameter in assessing acute iron poisoning. Studies are needed to develop a reliab le analytical procedure for TIBC and to correlate TIBC with clinical o utcomes in acute iron poisonings.