Understanding Your HbA1c: A Guide to Your 3-Month Blood Sugar

Direct answer: The Hemoglobin A1c (HbA1c) test is a simple blood test that measures your average blood sugar levels over the past 2 to 3 months. It's a key indicator used to diagnose prediabetes and diabetes, and to monitor how well a person's diabetes management plan is working. Unlike a daily glucose check, HbA1c provides a long-term view of blood sugar control, showing the percentage of hemoglobin proteins in your blood that are coated with sugar (glycated).

TL;DR The HbA1c test gives you and your doctor a picture of your average blood sugar levels over the last three months. It measures the percentage of your hemoglobin—a protein in red blood cells—that has sugar attached to it. A higher percentage indicates higher average blood sugar levels, which can signal prediabetes or diabetes. This test is crucial because it provides a long-term view, unlike the daily fluctuations you see with a finger-prick test, helping to assess your overall blood sugar management and risk for complications.

• What it is: A blood test showing your average blood sugar for the past 2-3 months.
• How it works: It measures the percentage of sugar-coated hemoglobin, known as glycated hemoglobin.
• Why it's important: It's a standard tool for diagnosing and monitoring prediabetes and type 2 diabetes.
• Normal Range: A normal HbA1c level is below 5.7%.
• Prediabetes Range: An HbA1c between 5.7% and 6.4% indicates prediabetes.
• Diabetes Range: An HbA1c of 6.5% or higher on two separate occasions indicates diabetes.
• Management Goal: For most people with diabetes, the goal is to keep their HbA1c below 7% to reduce the risk of long-term complications.

Want the full explanation? Keep reading ↓

HbA1c (Hemoglobin A1c) Reference Ranges

Feeling confused by your HbA1c result? Here's what it means.

So, you just got a lab report back with a number for "HbA1c," and now you’re probably scrolling the internet trying to figure out what it means. It can be frustrating and a little scary when you see a result, especially if it's flagged as high, and you don't know what to do next.

Let's break it down in simple terms. Think of the HbA1c test as a "loyalty card" for sugar in your blood. It doesn't just show your blood sugar at one moment in time, like a finger-prick test does. Instead, it gives your doctor a picture of your average blood sugar levels over the past 2 to 3 months.

What exactly is HbA1c?

Your blood contains red blood cells, which have a protein called hemoglobin (that’s the "Hb" part). Hemoglobin's main job is to carry oxygen.

When sugar (glucose) is in your bloodstream, it naturally sticks to this hemoglobin. The more sugar floating around, the more of it will stick. This sugar-coated hemoglobin is called "glycated hemoglobin," or HbA1c.

Since red blood cells live for about three months, measuring the percentage of your hemoglobin that is sugar-coated gives a reliable long-term average. A high HbA1c means you've had a lot of sugar in your blood over the last few months.

My HbA1c is high. What happens now?

Seeing a high number can be a shock, but it's also a powerful piece of information. It's a sign that your body is struggling to manage blood sugar. This is a critical moment to take action, but don't panic. Your result is a starting point, not a final verdict.

What causes a high HbA1c?

The most common reason for a high HbA1c is prediabetes or type 2 diabetes. This happens when your body either doesn't produce enough insulin (the hormone that moves sugar out of the blood) or can't use the insulin it makes effectively (a condition called insulin resistance).

Other factors that can increase your HbA1c include:

• Diet: A diet high in processed foods, sugary drinks, and refined carbohydrates.
• Lack of Physical Activity: Exercise helps your body use sugar for energy and improves insulin sensitivity.
• Stress: Chronic stress can raise hormones that increase your blood sugar.
• Poor Sleep: Lack of sleep can disrupt your hormones and make it harder to control blood sugar.
• Certain Medical Conditions: Conditions like Cushing's syndrome or polycystic ovary syndrome (PCOS) can affect blood sugar.

What does a prediabetes result (5.7% - 6.4%) really mean?

If you landed in this range, think of it as a warning light on your car's dashboard. It’s not a breakdown, but it’s a clear signal that you need to check under the hood. A prediabetes diagnosis means your blood sugar is consistently higher than it should be, and without changes, it's very likely to progress to type 2 diabetes.

The good news? This is your chance to make changes that can prevent or delay diabetes. Many people successfully lower their HbA1c back into the normal range with lifestyle adjustments.

My HbA1c is "normal," but I still feel unwell. What gives?

This is incredibly frustrating. Your doctor might have said your HbA1c is "fine," but you still feel tired all the time, have brain fog, or are gaining weight. While HbA1c is a great tool, it's not the whole story.

An HbA1c under 5.7% is considered normal, but it's an average. You could still be having significant spikes and crashes in your blood sugar throughout the day that your HbA1c average doesn't fully capture. These blood sugar rollercoasters can make you feel terrible even if your three-month average looks okay.

If you feel this way, it’s worth talking to your doctor about other tests, such as:

• Fasting Glucose: Measures your blood sugar after you haven't eaten for at least 8 hours.
• Fasting Insulin: Measures how much insulin your body is making while fasting. High insulin can be an early sign of insulin resistance.
• Continuous Glucose Monitor (CGM): A small wearable device that tracks your glucose 24/7, showing you exactly how your body reacts to different foods, exercise, and stress.

Frequently Asked Questions

What is the most common cause of abnormal HbA1c (Hemoglobin A1c) levels?

The most common cause is having more sugar in your bloodstream than your body can handle effectively. This is the hallmark of prediabetes and type 2 diabetes, where the body's ability to use insulin is impaired. Lifestyle factors like a diet high in sugar and refined carbs, lack of exercise, and chronic stress are the primary drivers.

How often should I get my HbA1c (Hemoglobin A1c) tested?

This depends on your results and your doctor's advice:

• If you have diabetes: Typically every 3 to 6 months to monitor how well your treatment plan is working.
• If you have prediabetes: Usually once every year to track your progress and see if your lifestyle changes are lowering your levels.
• If your result was normal: Your doctor may recommend re-testing every 3 years as part of a routine check-up, especially if you have risk factors like a family history of diabetes or are overweight.

Can lifestyle changes improve my HbA1c (Hemoglobin A1c) levels?

Absolutely. For many people, especially those with prediabetes, lifestyle changes are the most powerful tool for lowering HbA1c. Even a small amount of weight loss (5-7% of your body weight) can make a huge difference. Key changes include focusing on a whole-foods diet, reducing sugar and processed carbs, getting regular physical activity, managing stress, and prioritizing sleep.