What Is an A1C Test, and Why Does It Matter?

If you have diabetes, you know you need to check your blood sugar regularly. But do you know you also need an A1C test?

Blood glucose numbers only give a quick snapshot of blood sugar control at certain times of day. You may think your blood sugar is under control based on your daily glucose tests. But if you don’t happen to be testing at a time of day when your blood sugar level is high, you may not get the whole picture.

Why Does A1C Matter?

For an in-depth picture of how your blood sugar is doing, you need to know your hemoglobin A1C.  It gives you information about your average blood sugar levels over the last two or three months. It even measures what your blood sugar was when you were asleep.

It’s vital to know your average blood sugar levels over time. High levels are linked to serious health problems  and long-term complications, including eye, kidney, nerve and heart disease. These health problems can happen slowly, without you knowing it. Even a small improvement in your A1C level can significantly reduce your risk for complications.

If your blood sugar is well controlled, it’s recommended that you get the A1C test at least twice a year. If your blood sugar is not well controlled, you may need to be tested every three months to monitor your progress.

What Is the Target Range for A1C?

In general, if you have diabetes, an A1C of less than 8 is considered well controlled. Under 7 is very well controlled. If your number is above 8, better control is needed. And above 9 is considered very poor control.

Some things other than diet or diabetes medicines can make your number go up or down:

• Drugs such as opioids, steroids and statins and medicines for HIV, anxiety and depression
• Pregnancy, both in the early and late stages
• Kidney failure
• Liver disease
• Severe anemia

Talk to your PCP about what hemoglobin A1C number is best for you.

What If My A1C Is Out of Target Range?

First, talk to your doctor. You can work together to set goals and reach those goals. But your team includes others,  too. You may work with a:

• Nurse educator
• Registered dietitian
• Eye doctor
• Certified diabetes educator
• Endocrinologist who specializes in treating diabetes
• Foot doctor
• Dentist
• Pharmacist

Your team can coach, support and empower you through all your challenges. But remember that your health depends on you. Diabetes calls for a lifetime of learning and relearning. It is all part of the process of living with diabetes.

Sources: Diabetes tests and checkups,  U.S. National Library of Medicine, 2022; Preventing Diabetes Problems, NIDDKD; Your Health Care Team,  American Diabetes Association; Understanding A1C: A1C Looks Back,  ADA

Originally published 10/4/2022; Revised 2023, 2024