More Than Just a Number
If you have diabetes or prediabetes, your A1C is one of the most important numbers in your medical care. Yet many patients know their A1C value without truly understanding what it represents, how it relates to their daily blood sugar, or why small changes in this number can have significant health implications.
At Zimmer Medical Group, we believe that patients who understand their A1C are better equipped to manage their health. Here is everything you need to know.
What the A1C Test Measures
The A1C test (also called hemoglobin A1C, HbA1c, or glycated hemoglobin) measures the percentage of hemoglobin in your red blood cells that has glucose attached to it. Because red blood cells live for approximately 90 to 120 days, the A1C reflects your average blood sugar level over the past two to three months.
This makes it fundamentally different from a fasting glucose test, which captures a single moment in time. A fasting glucose can be normal one morning and elevated the next depending on what you ate the night before, how well you slept, or whether you are fighting an infection. The A1C smooths out these daily fluctuations and provides a reliable picture of your overall blood sugar control.
A1C Ranges and What They Mean
The American Diabetes Association defines the following ranges:
- Below 5.7%: Normal blood sugar control
- 5.7% to 6.4%: Prediabetes
- 6.5% or higher: Diabetes
Translating A1C to Average Blood Sugar
| A1C (%) | Estimated Average Blood Sugar (mg/dL) | |---------|---------------------------------------| | 5.0 | 97 | | 5.5 | 111 | | 6.0 | 126 | | 6.5 | 140 | | 7.0 | 154 | | 7.5 | 169 | | 8.0 | 183 | | 8.5 | 197 | | 9.0 | 212 | | 10.0 | 240 |
This conversion helps you understand what your A1C means in terms of the blood sugar levels your body experiences on a daily basis.
Why Small Changes in A1C Matter
A change of just 1 percentage point in A1C has significant health implications. The landmark United Kingdom Prospective Diabetes Study found that for every 1 percent reduction in A1C:
- Risk of diabetes-related death decreased by 21%
- Risk of heart attack decreased by 14%
- Risk of microvascular complications (eye, kidney, nerve damage) decreased by 37%
This means that bringing your A1C from 9% to 8%, or from 8% to 7%, produces meaningful reductions in your risk of serious complications, even if you do not reach the ideal range.
What Is Your Target A1C?
For most adults with diabetes, the general target A1C is below 7%. However, your individual target may be different based on several factors:
A Tighter Target (Below 6.5%) May Be Appropriate If:
- You are newly diagnosed
- You are younger with a long life expectancy
- You have no significant cardiovascular disease
- You can achieve this level without frequent hypoglycemia (low blood sugar)
A More Relaxed Target (7.5% to 8%) May Be Appropriate If:
- You have a history of severe hypoglycemia
- You have advanced cardiovascular disease
- You are older with limited life expectancy
- You have multiple coexisting medical conditions
Your healthcare provider will discuss your personalized target based on your complete health picture.
Factors That Affect A1C Accuracy
While the A1C is generally reliable, certain conditions can affect its accuracy:
- Anemia, blood loss, or recent transfusion can falsely lower or raise A1C
- Hemoglobin variants (common in certain ethnic groups) may affect some A1C assay methods
- Kidney disease can affect red blood cell lifespan and alter A1C reliability
- Iron deficiency can falsely elevate A1C
- Pregnancy affects A1C interpretation due to changes in red blood cell turnover
If your A1C does not correlate with your home glucose readings or your symptoms, discuss these factors with your doctor.
A1C Testing Schedule
- Prediabetes: Test annually to monitor for progression
- Diabetes (well-controlled): Test every six months
- Diabetes (adjusting treatment or not at goal): Test every three months
Your A1C is typically checked during routine blood work appointments and does not require fasting.
Beyond A1C: The Complete Picture
While A1C is the primary monitoring tool, it does not capture everything. Two patients can have the same A1C but very different daily glucose patterns. One may have stable blood sugar throughout the day, while another swings dramatically between high and low, averaging out to the same A1C.
Continuous glucose monitors (CGMs) and time-in-range metrics are increasingly used alongside A1C to provide a more complete picture of glucose control. Your doctor may recommend these tools if your A1C alone does not fully explain your glucose patterns.
Taking Control of Your A1C
Every aspect of your daily life affects your A1C: what you eat, how much you move, how well you sleep, how you manage stress, and whether you take your medications consistently. The good news is that each positive change contributes to improvement, and progress is measurable.
Track your A1C over time to see trends. A steadily declining A1C, even if you have not yet reached your target, means your changes are working. Celebrate that progress.
Want to better understand your A1C results or create a plan to improve them? Contact Zimmer Medical Group to schedule a diabetes management appointment. We are here to help you take control of your numbers and your health.
