Clinical determination of methemalbumin

We developed an assay for methemalbumin in biological fluids by using diethylaminoethyl-Sephadex ion-exchange chromatography to separate this protein from interfering components, including hemopexin, transferrin, hemoglobin, and haptoglobin/hemoglobin complex. Initial screening of the samples requires measurement of A280/A405 ratios of the peak tubes of the isolated albumin fraction. Values exceeding 30 indicate that methemalbumin is absent, and no further work is required. Values of less than 30 suggest that methemalbumin is present in the original sample, whereupon the presence and amount of methemalbumin can be ascertained by coloremetric assay for iron with use of ferrozine. Results may be expressed either in terms of micrograms of methemalbumin iron per gram of albumin or in milligrams of methemalbumin per liter. The reproducibility of the method is of the order of +/- 7% (SD). Normal persons have essentially no methemalbumin iron in their serum. Three individuals with hemorrhagic pancreatitis showed values of 65, 98, and 198 mug of methemalbumin Fe per gram of albumin.