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Confused About the HA1C Test? Here’s What It Means, and What It Doesn’t

Updated: Aug 25, 2023

If you’ve been diagnosed with prediabetes, your doctor has probably tested your HA1C. You may be aware that this number is related to blood sugar levels, but it’s important to understand both how it works and the pitfalls of relying too heavily on this test.

What is HA1C?

HA1C — often referred to as A1C — is shorthand for glycated hemoglobin. Stay with me here, I’ll explain.

Hemoglobin (the “H” in HA1C) is a red blood cell protein tasked with carrying oxygen throughout the body. “A1” tells us the type of hemoglobin — A1 makes up about 90% of the hemoglobin found in adults. And the “C” narrows down the type of hemoglobin even further.

What does HA1C have to do with blood sugar?

When you have prediabetes or diabetes, your doctor wants to keep track of your blood sugar (glucose) levels. Blood sugar that’s too high or too low can be dangerous. The best way to get a real-time measurement of your blood glucose is to test your blood.

But a blood test only tells you what is happening in your blood sugar at that exact moment in time. It’s also valuable to get a sense of your overall blood glucose pattern. That’s where the HA1C test comes in.

Glucose hangs out in your blood while your body delivers it to the cells to produce energy. And while it’s there, some of it attaches to the hemoglobin in your red blood cells. Hemoglobin that is coated with blood glucose is called ‘glycated’.

The HA1C test measures the amount of glucose that is stuck to your hemoglobin, or glycation.

The advantage to this test is that it can give you and your practitioner a picture of what your blood glucose is doing over time. Your hemoglobin cells live for about 3 months before they regenerate. So an HA1C test gives a picture of your blood glucose pattern over the past 3 months.

These are the HA1C levels your doctor is looking for:

  • An HA1C level of 5.6 percent is considered “normal”.

  • An HA1C level of 5.7 to 6.4 percent indicates prediabetes.

  • An HA1C level of 6.5 percent or above indicates diabetes

The problems with the HA1C Test

The HA1C test is not a perfect solution though, and it isn’t foolproof. There are factors other than blood glucose that can influence your results and give you a false reading.

One or more of these issues could affect your HA1C results:


This iron-deficiency can affect your red blood cells in a way that can skew your HA1C results. Iron-deficient people are more likely to have higher HA1C levels.

Low Thyroid Hormone Levels

Your thyroid hormones also affect your HA1C levels. If you have low thyroid function (hypothyroid), it can raise your HA1C numbers.

High Triglycerides

Triglycerides — a type of fat in the blood — also affect HA1C levels, especially if your diet is high in sugar.

Kidney Issues

If your kidneys are not functioning efficiently, it can lead to problems like anemia or other nutrient deficiencies. These can show up on your HA1C test as well.


Some medications — both prescription and OTC — can affect your HA1C results.

Vitamin B12 Imbalance

If your B12 levels are low it can lead to anemia, which can give you a false positive on your HA1C. If you’re taking B12 supplements and your levels are high, you can get a false negative, or low HA1C test result.

There are also other conditions that can affect your HA1C results like sickle cell anemia.

How to Use the HA1C Effectively

An HA1C test can be a valuable tool in your prediabetes management. It can provide information that isn’t readily available from any other source. But I get concerned when people focus entirely on their HA1C.

As I mentioned above, the test isn’t always accurate. Even factors in the lab like temperature or handling of samples can affect your test results. And even within an accurate test, it’s possible for the result to be off by as much as a point.

That doesn’t mean you shouldn’t have the HA1C test done, or even that you shouldn’t pay attention to the results. But in my practice, I like to make sure I have all the information for my clients with prediabetes, not just that one piece.

The HA1C shows you the overall pattern in an increment of 3 months. But it’s also important to see what’s happening with your blood glucose day-to-day. Testing your HA1C will not show you how your body reacts immediately after eating. And that’s important information.

I encourage my clients to monitor their blood sugar daily. There are a couple of ways to do this:

This is a device that measures your blood sugar levels in real time. It requires one drop of blood (usually from a fingertip) and it can tell you your current blood glucose levels.


  • Glucometers and the required testing strips are very affordable

  • They give accurate results in real time


  • While not terribly painful, finger sticks are uncomfortable. And doing them every day gets old.

  • If you want to test your blood sugar throughout the day, you have to keep both your glucometer and your testing strips with you even when you go out.

If you want to keep an accurate record of your blood glucose levels throughout the day without the finger sticks, a continuous glucose monitor (CGM) is the way to go. It includes a small wearable component that wirelessly connects to your smartphone.


  • No more finger sticks

  • Comfortable, waterproof, and easy to wear

  • Reliable results whenever you need them


  • These devices are much pricier than the glucometers

  • Some brands require a prescription

The Bottom Line

When you’ve got a prediabetes diagnosis, it’s important to pay attention to what’s going on. It is totally possible to reverse prediabetes by monitoring your blood glucose levels and making the appropriate diet and lifestyle changes can make all the difference — even preventing you from developing type 2 diabetes.

I’m a fan of using all the resources that are helpful and available. So that means taking advantage of the best testing options. But that also means being realistic about what the tests are telling you.


Did you know that a steam sauna can improve blood sugar?

Yes, that’s right! And there are many other ways to improve blood sugar. Addressing prediabetes doesn’t have to be hard. Ready to improve your blood sugar without changing your diet? Sign up for my FREE mini course, 10 Ways to Improve Blood Sugar Without Changing Your Diet. It’s a free email course, and it’s a fast and easy way to learn 10 impactful tips to begin balancing your blood sugar TODAY! Learn more



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