Glycated hemoglobin also called HbA1c is a form of hemoglobin linked to a sugar. The usual sugar is glucose. When once attached, glucose is not removed from hemoglobin. Therefore, it remains inside the erythrocyte, throughout the lifespan of RBC’s. HbA1c test measures the amount of blood sugar attached to hemoglobin. If your HbA1c levels are high, it may be a sign of diabetes, a chronic condition that can cause serious health problems, including heart disease, kidney disease and nerve damage. So the best index of long term control of blood glucose level is measurement of glycated hemoglobin. The HbA1c level reveals the mean glucose level over the previous 10-12 weeks. It is unaffected by recent food intake or recent changes in blood sugar levels. Normally the level of HbA1c is less than 5.5%. An elevated glycohemoglobin indicate poor control of diabetes mellitus. The American Diabetes Association recommends keeping your HbA1c level below 7% if you have diabetes. This test becomes less accurate for diagnosing diabetes if a person is suffering from anemia or any type of blood disorder.