A1C measures a sub-form of hemoglobin, which carries oxygen in your blood throughout your body. Sugar becomes attached to the A1C molecule and with high blood sugar, the A1C portion of hemoglobin also rises. Having elevated A1C can cause health concerns, such as diabetes.
The term A1C test refers to a blood test used to measure the amount of glucose, or sugar, linked to the hemoglobin in your blood. “An excessive presence of this linkage in the blood indicates diabetes or prediabetes,” says Casey Kelley, family doctor and specialist in integrative medicine.
Typically, A1C measures blood sugar levels over the past three months. It’s common for doctors and health care providers to use an A1C test to check if you’re prediabetic or to manage Type 1 and 2 diabetes. Other names for an A1C test include hemoglobin A1C, glycated hemoglobin, or a glycohemoglobin test.
At a doctor’s office, a phlebotomist will conduct these tests. Like other blood tests, blood is drawn from your vein and sent to a lab to be analyzed. An alternative way to check your A1C is to provide a sample through an at-home finger-prick test.