However, the doctor takes into account the patient's physical examination, symptoms and medical history to decide to test. The doctor uses this test to monitor the patient's diabetes control. Hemoglobin is the protein in red blood cells that transports oxygen. GHb forms when glucose in the blood attaches to the hemoglobin. The more glucose there is in the blood, the more glucose attaches to hemoglobin.
Blood cells remain in circulation for two to three months.
Therefore, GHb is a good measure of a person's average blood glucose level over the prior two to three months. High percentages of hemoglobin A1c mean a person's blood glucose has been high over a period of time. After the doctor has determined that a patient has diabetes, the doctor will consider many factors to determine which type of diabetes a patient has. Generally, persons with type 1 are diagnosed prior to age 30, are lean and have had diabetic ketoacidosis or high ketone levels in their urine. Type 2 individuals are diagnosed when they're over 30 years of age, obese and do not have urine ketones.