The what, why and how of A1c testing

Proper management of blood glucose levels is essential to avoiding complications such as kidney disease and nerve damage. While self-testing at home is one way to measure glucose levels, it only provides a momentary snapshot of your blood sugar. To gauge the overall effectiveness of your diabetes treatment plan, your doctor may order an A1c test.

What is A1c testing?

The A1c test may go by many names including glycated hemoglobin, glycosylated hemoglobin, hemoglobin A1C and HbA1c. It is a lab test which analyzes hemoglobin to determine how well your glucose has been controlled during the past 2-3 months. A1c testing is not a replacement for daily self-testing but is a valuable tool to determine whether your blood glucose is consistently at a safe level.

You may be able to have blood drawn at your physician's office for the test or you may be sent to a separate laboratory. The Mayo Clinic indicates there is no fasting requirement for this test so you may eat and drink normally before your appointment.

How does A1c testing work?

Hemoglobin is a protein in your red blood cells. It carries oxygen from your lungs to the cells in the rest of your body. When there is too much glucose in the bloodstream, it links up -- or glycates -- with the hemoglobin. This glycated hemoglobin is what the A1c test is measuring.

So while daily testing looks at your blood's current glucose level, the A1c test is looking for glycated hemoglobin. Since red blood cells can live up to 120 days, doctors can use the lab test to determine how well glucose has been controlled over the span of several months.

Health care professionals use the results of the A1c test to help determine the most appropriate treatment plan. Depending on how well your glucose levels are managed, your health care provider may prescribe medication or recommend lifestyle changes such as diet and exercise.

What do my test results mean?

Typically, individuals without diabetes have 5-6 percent of their hemoglobin glycated. According to the National Diabetes Education Program (NDEP), many health care providers set a target of 7 percent for their diabetes patients. The American Diabetes Association (ADA) reports those with uncontrolled diabetes can have A1c levels as high as 25 percent. Talk to your doctor to determine your individual target range.

When should I be tested?

The A1c test is traditionally used when making an initial diagnosis of diabetes. After that, the NDEP recommends getting the test done at least twice a year and perhaps more often depending on your situation. For example, women planning to get pregnant should be tested. In addition, the ADA recommends testing every three months for those who are starting a new medicine or treatment plan or when blood glucose levels are too high.

Does health insurance pay for A1c testing?

Medicare and most private health insurance plans cover A1c testing. Under the Affordable Care Act, diabetes screening is a mandated preventive service. That means health insurance companies must pay for this service without requiring a co-payment or co-insurance. Medicare beneficiaries may be eligible for up to two diabetes screenings each year. If you have private health insurance, contact your insurer to determine what coverage your plan offers.