1973 Volume 22 Issue 12 Pages 714-719
A part of transferrin in serum is binding iron, and the rest of it is designated as unsaturated iron binding capacity (UIBC) . The UIBC is defined as the capacity for binding iron. The sum of UIBC and serum iron content is total iron binding capacity (TIBC) . In general, UIBC and serum iron content are in inverse proportion with each other, but the value of UIBC is also variable owing to the increase and decrease of transferrin.
Although a lot of chemical methods have been applied to the determination of UIBC, it is troublesome to keep the experimental apparatus free of iron and it is not easy to prepare the standard solution of iron. Since a several years the authors have been em-ploying the method using 59Fe for the determination of UIBC. A few of studies on this method were made, and the results are reported here.
Results: The differences in the duplicated determination of UIBC were found to be 0.2-32.0 (14.2) μg/dl. Notable differences were observed in the case of hyperferremia. This indicates that much cautions should be taken for the determination of UIBC which is of low value.
Under consideration of the effect of temperature on the reaction rate, the preferred incubation time was studied at 22°C and 37°C. At 22°C the reaction continued along with time, while at 37°C the reaction reached to plateau after 30 min, and thereafter the rate of reaction was almost constant.
The effect of skill in measuring of the serum volume on the value of UIBC was little in the case of hyperferremia, however it was very notable in the case of normal and hypoferremia.
The serum iron content and the value of UIBC which were determined at the same time correlated inversely to each other, although there were variations in each case.
The normal values of UIBC were found to be 163-265 (211±37. 5) μg/dl in 21 men and 148-275 (215±32.8) μg/dl in 23 women, respectively.