A hemolyzed preparation of the whole blood is mixed continuously for five minutes with a weak binding cation-exchange resin. During this time, HbA0 binds to the resin. After the mixing period, a filter is used to separate the supernatant containing the glycohemoglobin from the resin. (Note: This binding is temperature dependent. Therefore, a standard should be included in each run.) The percent glycohemoglobin is determined by measuring the absorbance at 415 nm (405-420 nm acceptable) of the glycohemoglobin fraction and the total hemoglobin fraction. The ratio of the two absorbances gives the percent glycohemoglobin.