Blood glucose (sugar) is derived from food and it is the main source of energy. If a person has high blood glucose level then this condition is known as diabetes while if it is low it is known as hypoglycemia. Diabetic patients should monitor their glucose or HbA1c levels regularly to evaluate control of blood glucose in body. Diabetes mellitus, commonly known as diabetes, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased appetite. If left untreated, diabetes can cause many health complications.