HbA1c Test and Diabetic Complications

The word diabetes originated from Greek word for "flow through," since two of the most common warning signs are excessive thirst and need to urinate frequently. In the pancreas there are special cells known as islets of Langerhans. Nearly 75% cells of these islets produce hormone insulin which decreases blood glucose level and rest 25% produce another hormone, glucagon which increases blood sugar level. In normal persons, blood has glucose after food intake. As a result the insulin is secreted to convert blood glucose into glycogen and fat for storage. In diabetes, there is a trouble with insulin.

There are two types of diabetes, type I & II. In type I body does notmakeinsulin as the pancreatic cells responsible for insulin are damaged. In type II, body does not have increased insulin because of insulin resistance. As a result, in both the conditions blood sugar levels become very high causing hyperglycemia. Most of the symptoms of diabetes are similar for type I and type II diabetes. These symptoms include: Excessive thirst and urination, fatigue, weight loss, nausea, irritability, blurred vision, delayed healing of wounds, frequent infections, mood fluctuations.

When glucose is present in the blood, it attaches to the haemoglobin making it glycosylated haemoglobin or HbA1c. When there is more glucose in the blood more HbA1c will be formed. The amount of glucose attached to haemoglobin (Hb) is measured in this test. The HbA1c test is performed at three month interval when glucose level is high and it needs to be brought down. In case blood glucose level is well within control and gives stable results, the tests are performed every six months intervals. The long-term or chronic complications of diabetes are those that characteristically occur after years of high blood sugar levels. These are diabetic macrovascular and microvascular diseases. The long term complications correlate well with A1c levels. The clinical laboratories should, however, be careful of the interferencesproduced in assays by variant Hbs. The majority arise from point mutations in the alpha, beta, gamma or deltaHb chains. Moreover, since ethnic minorities have mean A1c concentrations significantly different from whites, So it is to be ascertained whether A1c can be used as a diagnostic test for diabetes detection and control.

The glycohaemoglobin values in the "better ranges" correlate with less incidences of diabetic complications later in life. Type 1 diabetics will typically have hemoglobin A1c levels determined every 3 to 4 months, while Type 2 diabetics will require measurements less often. It so because Red blood cells are replaced in about 90 days thus test gives blood glucose levels for that period. Normal blood glucose levels are below 6 percent HbA1c, however, these vary laboratory to laboratory. HbA1c levels compare well with blood glucose levels.