Screening test for iron overload.

It is presently estimated that 2-3/10(3) people living in the United States are homozygous for the iron-loading gene and are thereby susceptible to severe iron overload. The complications of this disorder can be prevented if recognized in the asymptomatic precirrhotic stage. We have developed a simple, inexpensive screening method for its early laboratory detection based on the fact that one of the earliest laboratory manifestations of hemochromatosis is a reduction in unsaturated iron-binding capacity. The sequential addition of a small measured quantity of saturating iron and bathophenanthroline disulfonate will result in color with highly saturated but not with normal sera. This screening test almost completely differentiated between 40 normal individuals and 40 patients with iron overload (as defined by a transferrin saturation greater than 55%). The test provides a cost-effective method for screening large segments of the population to detect this genetic disorder.