A1C is another term for 'Glycated Hemoglobin' which in turn can also be known as glycosylated hemoglobin, and confusingly 'HbA1C, A1C, Hb1C or HbA1C. This is a form of hemoglobin that is used in medicine to identify plasma glucose concentration over time. What does that mean in plain English? Well as hemoglobin that means that it is a red blood cell and a protein which is used in order to carry oxygen around the blood. It is called glycated hemoglobin due to its exposure to glucose which has resulted in its transformation.
It then used to identify plasma glucose concentration – what does that mean? Well plasma is the yellow liquid part of the blood which is used to heal wounds and to suspend the other blood cells. We normally think of it for its clotting factor which allows it to form scabs, but actually it is an important part of the fluid in our blood (it is 98% water). Glucose meanwhile is the primary form of energy in the body which comes from the carbohydrates in our diet and from which we can get ATP after it has reacted with oxygen in order to power our muscles and organs. While glucose is important, too much glucose can suggest a problem such as diabetes as it means that the body is not correctly employing its insulin in order to convert that glucose into useable energy. This then results in excess glucose free in the blood stream which can cause damage to our nerves and organs etc, which is how diabetes is characterized.
How the Test Is Used
Normally when we hear the term A1C this is referring to a test that is conducted in order to test for abnormal levels of glucose in the plasma. As the plasma makes up 55% of blood volume this is a good indicator for diabetes or other conditions.
Glycated hemoglobin is created by exposure to glucose in the plasma. As such this then means that the amount of glycated hemoglobin is a good indicator of the amount of glucose and can tell doctors precisely how much plasma glucose is in the system.
So why is this used rather than just looking at the amount of glucose directly? The answer for this is simple; because the amount of glucose changes rapidly on a day to day basis as we eat sugary foods. This then means that this wouldn't necessarily indicate a problem, but rather just what you had eaten that day – you would need to conduct many blood tests over a prolonged period of time to identify a concerning pattern. However as A1C takes a while to be produced through extended exposure to plasma glucose, this then means that the amount of A1C can tell doctors what the blood levels of glucose have been like over that extended period of time. Roughly this will tell them how your blood sugar has been six to twelve weeks prior to the test and can be used alongside blood sugar monitoring to look for problems with your blood sugar levels. Doctors will then use this to identify the presence of diabetes in a patient, and also to monitor their treatments to see if they have been effective.
How the Test Is Performed
The A1C test will be performed as any blood test – you will have some blood removed with a syringe and this will normally be taken from the inside of the elbow or back of the hand. The Nurse may place an elastic band around the upper arm in order to cause the veins to swell with blood. From here your blood will then be taken and sent away from testing. When you get your results you will want to find an HbA1C of under 6% – this is roughly normal. If it is around 6.5% or higher then you may be diagnosed with diabetes. If you already have diabetes then the ambition is to try and keep it below 7% – but this will depend on the individual and your doctor will inform you what your individual results mean for you.