The A1C test is a blood test that can be used to monitor how well your type 2 diabetes treatment plan is working. The test measures your average blood sugar levels over the past 2 to 3 months.

A1C tests results are given as a percentage. The higher the percentage, the higher your blood sugar levels have been over that time.

For many people with diabetes, the A1C goal is 7 percent or less. This goal may differ from person to person, though, depending on age and any additional medical conditions. You should speak with your doctor about the goal that’s right for you.

If you’ve been following your type 2 diabetes management and treatment plan but you’re not hitting your A1C goal, it doesn’t mean you’ve failed or done anything wrong.

Many factors can impact your A1C results. Some are out of your control, and others you can take steps to manage.

Here are 10 reasons your A1C may not be at goal.

Over time, you may notice that it becomes harder to hit your blood sugar targets, even if you’re still following the same diet, exercise, and treatment plans. That’s because type 2 diabetes is a progressive condition.

The cells in your body may stop responding to insulin produced by your pancreas. And eventually, your pancreas may produce less insulin or stop producing insulin altogether.

As type 2 diabetes progresses, your treatment plan may no longer work as well as it used to. You may need to work with your doctor to adjust your medication in order to hit your A1C goal.

Studies estimate that A1C levels will increase roughly 1 percent every 2 years, even with most diabetes treatments.

You can still take steps to manage your blood sugar by working with your doctor, making lifestyle changes, and taking your type 2 diabetes medication as prescribed.

A number of hormonal changes can affect your A1C level.

Menstruation and menopause create hormonal changes in your body, which can then affect blood sugar levels for women.

Physical or emotional stress can also play a role in your A1C level. Stress triggers the release of hormones that can raise your blood sugar level, which can cause your A1C to increase as well.

If you’re experiencing hormonal changes, you can talk with your doctor about adjusting your treatment plan, if needed.

You can also ask your doctor about ways to manage stress. Stress-relieving activities may include:

  • exercising
  • practicing relaxation techniques such as meditation or yoga
  • spending time with family and friends
  • doing a hobby you enjoy

Some research shows that A1C results can be falsely low in pregnant women, especially those in the second or third trimester.

Pregnancy alters the lifespan of red blood cells, which can affect A1C results.

You may have different blood sugar and A1C targets during your pregnancy. Talk with your doctor about the goals that are right for you and whether you need to adjust your treatment plan to meet those goals.

Certain diabetes-related complications can make it harder to manage blood sugar, which can impact your A1C result. For example, gum disease, a common complication of diabetes, can raise your blood sugar levels.

Chronic kidney disease (CKD) is another condition common in people with diabetes. Research shows that A1C may not be a reliable measure of blood sugars levels in people with diabetes and CKD.

Kidney failure and complications of CKD, such as anemia, may cause falsely high A1C results.

Seeing a doctor regularly can help you prevent or manage diabetes complications and related health conditions. Other potential complications include:

  • heart disease
  • nerve damage
  • eye or vision problems
  • foot problems

Your doctor may also recommend you see a specialist, such as a cardiologist or an ophthalmologist if you have diabetes-related complications.

Certain medications, such as opioids and some HIV medications, may cause falsely high A1C results.

Talk with your doctor about any medications or supplements you take and how they may impact your A1C.

The lifespan of red blood cells is one of the biggest influences on A1C levels.

That’s because the A1C test measures the percentage of your red blood cells that have glucose attached to the hemoglobin, a protein in red blood cells.

Changes in red blood cells can change your A1C. If you’ve recently experienced blood loss or had a blood transfusion, your A1C results may be inaccurate.

People with very low iron levels might experience a falsely high A1C result.

This is especially true for individuals with iron-deficiency anemia, a common type of anemia caused by a lack of iron. Iron is needed to make new red blood cells to replace older red blood cells.

If you have unusually high A1C levels and suspect anemia may be the cause, it’s a good idea to talk with your doctor and do further testing if needed.

Type 2 diabetes can progress or change, which means sometimes a different treatment approach might be necessary to manage your A1C level.

If your treatment is no longer effective and is impacting your blood sugar levels, talk with your doctor about making an adjustment. You may need to:

  • start taking medication if you’re currently managing with diet and exercise
  • change the dosage of your current medication
  • switch to a new medication
  • switch from oral diabetes medications to insulin

Your blood sugar naturally fluctuates throughout the day. Many things can impact your blood sugar, such as:

  • the amount of carbohydrates you eat
  • your physical activity level
  • quality of sleep
  • stress

Fluctuating blood sugar can affect your A1C readings, which is the average of your blood sugar over a few months.

Testing your blood sugar regularly can help you see how certain factors affect your blood sugar and help you stay in your target range.

Sometimes, an A1C test can be affected by external factors outside of your control.

Surprising influences like temperature, equipment used, and even how samples are handled in the lab can cause falsely high or low A1C results.

If you suspect a false result due to external sources, ask your doctor to repeat your A1C test.

It’s important to manage type 2 diabetes to help prevent the disease from progressing.

Sometimes, even those who follow their diet, exercise, and treatment plans may experience higher or lower A1C levels.

This doesn’t mean you’re doing something wrong. Instead, it could be indicative of changes to your condition or other factors impacting blood sugar levels, such as pregnancy or medication.

If your A1C isn’t at goal, consult with your doctor to identify possible factors and discuss changes to treatment, if necessary, to help get your blood sugar levels to numbers that are right for you.