Glycosylated hemoglobin: Glucose in the blood combines with Hemoglobin to form glycohemoglobin. This forms in the red blood cells in their life span of 120 days. Hence, glycosylated hemoglobin indicates the level of glucose. The stress or food could be the main cause of the high values. Hence, it is easier to take readings compared to the fasting blood. Blood glucose monitoring is very important for diabetic patients.