If you’ve ever had a blood test at your doctor’s office, there’s a good chance your A1C level was measured — or it will be at some point. For people managing diabetes, the A1C is one of the most closely watched numbers in their health profile. For everyone else, it’s an important screening tool that can catch prediabetes long before it becomes a bigger problem. And yet, for many patients, the result arrives with very little explanation. What does the number actually mean? What causes it to go up? And what can you do about it? At Trusted Care Clinic in Richardson, TX, Dr. Rofaida El Haj Mousa helps patients make sense of their A1C results and understand what steps to take next.
What Is the A1C Test?
The A1C test — also called HbA1c, haemoglobin A1c, or glycated haemoglobin — measures the percentage of haemoglobin in your red blood cells that has glucose (sugar) attached to it. Because red blood cells live for approximately two to three months, the A1C gives a view of your average blood sugar levels over that entire period, rather than just what it happened to be on the day of your test.
This is what makes it different from a fasting blood glucose test, which only captures a single snapshot in time. The A1C is more like a three-month average — a broader, more revealing picture of how your blood sugar has been behaving.
How Is the Test Done?
An A1C test requires a blood draw — typically from a vein in your arm, though some offices use a finger-prick test. Importantly, it does not require fasting before the test. You can eat and drink normally beforehand, which makes it much more convenient than a fasting glucose test.
Understanding Your A1C Results
| A1C Level | Classification | What It Generally Indicates |
| Below 5.7% | Normal | Blood sugar levels are within a healthy range |
| 5.7% – 6.4% | Prediabetes | Blood sugar is elevated but not yet at diabetic levels |
| 6.5% or higher | Diabetes | Meets the diagnostic threshold for type 2 diabetes |
| Below 7% (for diagnosed diabetics) | Well-controlled | Indicates good blood sugar management; target varies by individual |
Note: These are general reference ranges. Your physician will interpret your result in the context of your age, health history, and individual risk factors. Targets for people with diabetes vary — some individuals, particularly older adults, may have different target ranges recommended by their care team.
What Causes A1C Levels to Rise?
A1C rises when blood glucose levels have been consistently higher than normal over the preceding months. This can be caused by:
- A diet high in refined carbohydrates and added sugars
- Physical inactivity
- Weight gain, particularly around the abdomen
- Stress, which affects blood sugar regulation
- Certain medications that raise blood sugar levels
- Conditions like polycystic ovary syndrome (PCOS), sleep apnoea, or thyroid disorders that affect insulin sensitivity
- Family history of type 2 diabetes
What About False Results?
A1C results can be affected by certain medical conditions that alter how long red blood cells live. Conditions like anaemia, sickle cell disease, kidney disease, or certain haemoglobin variants may produce falsely high or low A1C readings. If your doctor suspects this, they may use an alternative test to assess blood sugar control.
What Happens If Your A1C Is in the Prediabetes Range?
A prediabetes result is significant — but it’s also an opportunity. Research has consistently found that lifestyle changes at the prediabetes stage can delay or prevent progression to type 2 diabetes. The interventions most supported by evidence include:
- Modest weight loss — even 5 to 7% of body weight has been shown to make a meaningful difference
- Regular physical activity — aiming for 150 minutes per week of moderate-intensity exercise is a common recommendation
- Dietary changes — reducing refined carbohydrates, increasing fibre, and limiting processed foods
Your doctor may also discuss whether medication is appropriate based on your overall risk profile.
How to Lower A1C if It’s Already in the Diabetic Range?
For people with an established diabetes diagnosis, A1C management is a central part of care. Strategies typically involve:
- Blood sugar monitoring as recommended by your care team
- Medication adherence — whether oral medications or insulin
- Consistent dietary management with support from a registered dietitian where available
- Regular exercise
- Attending regular check-ins with your physician for A1C monitoring every three to six months
A1C is not a permanent verdict. With consistent attention, many patients bring their numbers down significantly over time.
How Often Should A1C Be Tested?
For adults without diabetes who are at average risk, A1C may be checked at routine physicals every few years after age 45, or earlier if risk factors are present. For people with prediabetes, annual testing is typically recommended. For people with type 2 diabetes, testing is usually done every three to six months, depending on how well blood sugar is being managed.
Closing Thought
An A1C result is one of the most useful single numbers your doctor can have when assessing your metabolic health. If you haven’t had yours checked recently, it’s worth adding to your next visit at Trusted Care Clinic — particularly if you have risk factors for diabetes or prediabetes.
Frequently Asked Questions
Can A1C be affected by what I ate the night before?
No — because A1C reflects an average over two to three months, a single meal won’t change it. This is one of the advantages of A1C over fasting blood glucose tests.
Can A1C be normal even if I sometimes have high blood sugar?
Yes. Occasional blood sugar spikes that come back down quickly may not significantly affect the A1C average. However, consistently elevated levels — even if not always flagged on a daily test — will push the A1C up over time.
How fast can A1C change?
Because it reflects a three-month average, meaningful changes in A1C take time to show up — typically two to three months of consistent change in blood sugar management before a significant shift appears in the result.
Is a higher A1C always worse?
Generally yes, in the context of diabetes risk and management. However, a very low A1C in someone with diabetes may indicate episodes of low blood sugar, which has its own risks. Target ranges are individualised.
Do I need to fast for an A1C test?
No. Unlike a fasting blood glucose test, the A1C test does not require fasting. You can eat and drink normally before having it drawn.
Can children or teenagers have elevated A1C?
Yes. Type 2 diabetes in young people has become more common, and A1C is used in that population as well. If there are concerns about a child’s blood sugar, a physician can advise on appropriate testing.
Medical Disclaimer: The information in this blog is for general educational purposes only and does not substitute professional medical advice. A1C ranges and targets vary by individual. Your healthcare provider is the appropriate person to interpret your results and recommend any changes to your care plan.
