A1c test is a laboratory test to determine the percentage of glycosylated hemoglobin in blood over the past two to three months. The A1c test is useful to help gauging the sugar control of the last 90 days in someone with diabetes.
A1c test is sometimes known as hemoglobin A1c, HbA1c, glycosylated hemoglobin and glycated hemoglobin. Nonetheless, it is a standardized test to assist doctors monitor control of sugar. The test is usually done every quarter of the year in those newly diagnosed diabetes and less frequent when good sugar control is achieved. The A1c test is not limit to type 2 diabetes only; in fact it is recognized world wide as diagnostic test and management test for both type 1 and 2 diabetes.
How does the A1c test works?
The A1c test or glycosylated hemoglobin base its results on the concept of excess sugar in blood will bind to hemoglobin. Our red blood cells are filled with hemoglobin that carries oxygen and travels around the body. Extra sugar in blood will enter the red blood cells and bind or glycate to the hemoglobin. The A1c test actually measures the percentage of sugar attached or glycated to hemoglobin. The higher the value is, the more sugar is in the blood, meaning poor sugar control.
The A1c test is only performed at most every quarter of the year because the binding to hemoglobin is irreversible and that correlates with lifespan of red blood cells which is generally about 90 days. Keeping track of the results will let doctors determine if diabetes is under control and to ultimately reduce complications of diabetes like heart attacks and kidney failures.
Why is A1c test important?
Before initiating therapy for diabetes, doctor will do the Diabetes A1c test to confirm diagnosis of diabetes as well as using it as baseline result for evaluating therapy. Any result higher than 7% is a diagnosis of diabetes. It is important after starting therapy that doctor repeats the A1c test to ascertain efficacy of therapy, deciding on need to add on new therapy perhaps or further lifestyle changes needed.
Every 1% reduction of A1c test is expected to minimize progression of diabetes to its complications particularly kidney failure and cardiovascular risks. It was demonstrated that intensive therapy to reduce A1c is also associated with lesser microvascular complications including numbness of limbs and retinopathy (loss of visions).
There are of course some limitations to the HbA1c test too. One must always remember the test result only reflects the overall sugar control over the last two to three months. It does not show the immediate sugar level. Therefore, for those on insulin therapy, routine daily blood sugar level with glucose meter is still essential to monitor and to titrate insulin doses. The A1c test cannot replace glucose meter in this instance. Furthermore, the effect of anemia (or those with low red blood cells) on the results of A1c test is still debatable.
A1c test is now recognized as part of routine diabetes care both for diagnosis as well as management tool of diabetes therapy. It is very useful for the doctors to assist in halting progression of the diabetes.