Understanding the A1C Test: Your Guide to Diabetes Management
What is the difference between A1c and Time in Range, and how can they affect your diabetes management?
LAB TESTSGLUCOMETERS
Kelly Robers
4 min read
What Is the A1C Test Anyway?
If you have ever walked out of your doctor's office confused about your A1C, you are not alone. Between the percentages, numbers, and doctor-speak, it can feel more like a math test than a health check.
But here's the bottom line: Your A1C is a powerful snapshot of your average blood sugar levels over the past 2–3 months. It's one of the most important tools for managing diabetes—think of it as your "report card," but without the pressure or red pen. The test measures the amount of glucose (sugar) attached to your red blood cells. Since red blood cells only live for about 3 months, your A1C provides a bigger picture than daily finger sticks.
Why It Matters
An A1C test helps you and your care team:
✅ Understand your overall blood sugar control
✅ Adjust medication, lifestyle, or nutrition plans
✅ Prevent complications from sneaky, long-term high blood sugars
Most adults with diabetes should aim for an A1C around 7%. However, your target might be higher or lower, depending on your age, health conditions, whether you frequently experience low blood sugars, or whether you're pregnant.
Here's a Quick Cheat Sheet:
| A1C Level | Estimated Avg Glucose (mg/dL) | What It Means |
|------------------|------------------------------------|-----------------------------------------|
| Below 5.7% | Under 117 | Normal (non-diabetic range) |
| 5.7%–6.4% | 117–137 | Prediabetes |
| 6.5% or higher | 140+ | Diabetes diagnosis range |
| 7%–8%+ | 154–183+ | May need management adjustments |
But Wait—A1C Isn't Perfect
Here's the thing your lab report won't tell you: A1C has some limitations. It's a useful average—but just like any average, it can be misleading.
🧬 Factors That Can Affect A1C (Outside of Blood Sugar)
Anemia or iron deficiency
Kidney or liver disease
Certain genetic traits (like sickle cell or thalassemia)
Recent blood loss or transfusion
Race and age differences (A1C may read higher in some populations)
If your red blood cells are living shorter or longer than average, your A1C might not tell the whole story.
CGMs and A1cs don't always agree on whether blood sugar levels are where they should be.
A1C vs. Time in Range: The New Gold Standard?
If you use a Continuous Glucose Monitor (CGM), you may have heard the term Time in Range (TIR). This is the percentage of time your blood sugar is within your target range (usually 70–180 mg/dL).
Why Time in Range Matters:
It shows day-to-day ups and downs
It helps you catch highs and lows that A1C might miss
It's more personalized and actionable
You can have an A1C of 7% and still be bouncing between 50 and 250 every day. TIR helps fill in those gaps.
TIR Goal: At least 70% of the time in range = roughly an A1C of 7% (But again, the target may vary based on your plan.)
Bottom line: A1C is helpful, but it's not the whole picture. If you're using a CGM, talk to your provider about balancing A1C and Time in Range.
What Causes a High A1C?
It's not just about willpower or sweets. Many factors can cause your A1C to rise:
Skipping or mistiming meds
Insulin resistance
Stress or illness
Poor sleep
Hormonal changes (hello, menopause!)
Unmanaged snacking (we see you, late-night pantry raids)
Sometimes, you're doing everything right, and it still creeps up. That's why A1C should be one part of the bigger picture—not the whole story.
How to Lower It (Without Losing Your Mind)
If your A1C is higher than your target, don't panic. It doesn't mean you failed. It means your body is asking for some extra help—and that's where simple, sustainable changes can shine. Here's what helps:
🍽️ 1. Eat Balanced Meals
Focus on meals that combine carbs with protein, fiber, and healthy fats. Check out our previous post on how to build your plate or make an appointment to meet with us to work one-on-one. The plate method is your friend:
½ non-starchy veggies
¼ lean protein
¼ whole grains or starch
Add a piece of fruit or dairy if it fits your plan.
🏃 2. Move Your Body (Even Just a Bit)
Exercise helps lower blood sugar right away and improves insulin sensitivity over time. Aim for 150 minutes per week of moderate movement; that's the gold standard.
💊 3. Take Medications as Prescribed
Medications (like metformin or insulin) aren't a punishment; they're tools to help your body do things it can't do for itself. If you're experiencing side effects, struggling with the cost, or facing challenges with timing, consult with your healthcare provider for guidance.
🧘 4. Manage Stress & Sleep
Stress hormones, like cortisol, can raise blood sugar. Try deep breathing, meditation, or journaling to help you relax. Aim for 7–9 hours of sleep; your blood sugar will thank you. If you test your blood sugar around stressful situations, you might get a better idea of how much this affects you. Talk to your doctor about medications to help with this if you frequently need to do so, like taking tests or public speaking.
📅 5. Test Strategically
Whether you're using finger sticks or a CGM, testing gives you real-time feedback. It helps you spot trends and make small changes that add up. Check out our Goal log to help you identify trends.
A1C Is a Tool, Not a Judgment
Your A1C doesn't measure your worth. It doesn't reflect how hard you're trying. It doesn't even tell you if you are doing a good job. It's simply data, a helpful tool to guide your next steps. And the good news? You have more control than you think.
✅ Takeaway Message:
The A1C test is a key part of diabetes management, but it doesn't tell the whole story. Time in range and real-life patterns matter just as much. Focus on small, sustainable habits and use all your tools—not just one number—to guide your path.