Provided herein are methods for detecting glycated hemoglobin in, for example, human whole blood, that are not affected by the presence of variation in amino acid sequence that can exist in hemoglobin β chains. The methods detect all glycated hemoglobin in a sample, regardless of the form of the hemoglobin that has been glycated, and thus detect glycated human Hemoglobin A, Hemoglobin S, and Hemoglobin C.