Patent ID: 7195923

Claim:
A method for determining a ratio of an amount of a glycated form of a protein to a total amount of the protein in a sample containing both glycated and nonglycated forms of the protein, comprising: providing a solid support having negatively charged carboxyl groups immobilized thereon, which groups are capable of binding both the glycated and the nonglycated forms of the protein at a first pH, said support also having hydroxyboryl groups immobilized thereon, interspersed with the negatively charged carboxyl groups, which hydroxyboryl groups are capable of binding the glycated form of the protein at a second pH; adding the sample to the solid support at the first pH, thereby binding both the glycated and the nonglycated forms of the protein to the negatively charged carboxyl groups on the solid support, and then performing a first measurement indicative of the total amount of the glycated and the nonglycated forms of the protein bound to the solid support; changing the pH on the support to the second pH, thereby removing both the nonglycated form of the protein and the glycated form of the protein from the negatively charged carboxyl groups, after which removal the glycated form of the protein immediately binds to the hydroxyboryl groups on the support independent of incubation time, and then performing a second measurement indicative of the amount of the glycated form of the protein bound to the solid support; and determining the ratio of the amount of the glycated form of the protein to the total amount of the glycated and the nonglycated forms of the protein in the sample from the first and second measurements.