High fasting blood sugar but normal a1c

Are you worried you’re at risk of diabetes because of high blood sugar levels on your A1C test? Does your blood sugar spike even when you’re eating healthy foods like apples and pears? 

While high blood sugar is a common sign of diabetes, it’s not exclusive to those with the health condition. In fact, people often encounter high levels even if they don’t have a history of diabetes. 

What is the A1C Test Measuring?

There can be several reasons for a spike in blood sugar levels, and it’s a good idea to know what’s causing yours. But first, it’s essential to understand what A1C is and what the A1C test measures. 

Any sugar that enters your bloodstream attaches itself to your hemoglobin on your red blood cells. The A1C test measures the amount of glucose “stuck” to the hemoglobin, which provides a good proxy of how much average blood glucose was in your bloodstream over a two to three-month period. 

A simple way to remember how to read the results is: the higher the percentage, the higher the risk of diabetes. According to the Centers for Disease Control and Prevention, under 5.7% is a regular A1C reading. A reading between 5.7% and 6.4% is considered a pre-diabetic range, while values above 6.4% indicate diabetes. 

Before you start overanalyzing your results, remember that there are variables at play. For example, the U.S. National Library of Medicine (NLM) found that adults without a history of diabetes often have A1C levels at 6% or greater. This means not every higher test result is cause for concern. Still, it’s worth checking with a doctor if you see consistently high values. High A1C levels lead to impaired fasting glucose, and an increased risk of type 2 diabetes and cardiovascular diseases.

8 Reasons Your A1C Results Came Back High Even Though You’re Not Diabetic

From vitamins to chronic health issues, there are many reasons for a high A1C result. Here are eight of the most common reasons.

1. You Have Anemia

Any interference with your red blood cells or changes in hemoglobin will falsely skew the results of an A1C test. Anemia, usually caused by a lack of iron or deficiencies in vitamins B12 or B9, is a good example. 

According to a 2014 study, iron-deficient individuals had higher A1C more frequently. Those with fasting blood glucose saw even more elevated levels. And, when classified by gender, women recorded higher levels. As anemic patients usually have a shortage of healthy red blood cells, you can see false-high A1C values even if you don’t have diabetes. 

2. You Have High Triglyceride Levels

Your triglycerides are a type of fat in your blood, serving as an energy source for your body. Your body can convert energy it doesn’t need to burn right away into triglycerides. It then uses them as an energy source between meals.

 The NIH has found that A1C levels can be an indicator of your triglyceride count. If one is high, the other most likely is as well. This is especially true if your diet is high in added sugars.

3. You Have Kidney Disease or Related Disorders

Those who suffer from kidney disease can find it more challenging to rely on the efficiency of A1C tests. They often see high A1C results, according to a report by DaVita Inc., that may not always be accurate. This is because kidney disease can cause complications like anemia and malnutrition. This, in turn, affects the results of an A1C test. With both diabetes and kidney disease, it can be more challenging to get accurate results. 

4. Some Medications Such As Opioids Can Cause High A1C Levels

Several different medications can interfere with A1C test results. Some can even cause errors in readings or bring up inaccurate results. Some opiates and even over-the-counter drugs can increase your A1C levels. According to a study by the NIH, common drugs like aspirin also cause high or low A1C levels. 

Of course, taking the occasional aspirin won’t affect your levels too much. It usually only starts to skew the results of an A1C test if you are taking these medications at regular, larger doses over a long period. This isn’t a one size fits all rule, though. For example, among those with type 2 diabetes, aspirin didn’t show any elevated levels at all. 

5. You Have Disorders Related to the Spleen

Spleen disorders, like sickle cell or asplenia, can also affect your A1C tests. If you think your levels are suspect and have one of these disorders, that may be the culprit. As the NIH found, these disorders render tests less accurate when a patient inherits a hemoglobin variant. 

There’s a word for this group of inherited disorders passed down over generations. Take a deep breath before you attempt to say it—they're called hemoglobinopathies. If you suffer from any of this, you could start to see false highs in your test results.

6. You Have Low Thyroid Levels

Quick review: thyroid hormones regulate the rate at which your body burns calories. The number of thyroid hormones in the bloodstream can affect your A1C level. This will cause the reading to fluctuate or give you false results. For example, hypothyroidism, or a low thyroid hormone levels, can lead to an elevated level of A1C.

7. You Have Hemoglobin Type C, D, or E

Did you know there were various variants of hemoglobin? It’s not common to know your type, but if you’re wondering what’s leading to elevated A1C levels, you may want to check. The most common is Hemoglobin A. 

According to research by the government in British Columbia, Canada, there are 350 varieties. Type C, for example, doesn’t carry oxygen very well, which can affect A1C levels. Then there’s Type E, an inherited blood disorder most common among people of Southeast Asian descent. It can also record false high levels of A1C in your system. To find out what types you have, it’s a good idea to take a blood test called the hemoglobin electrophoresis test. 

8. You Have a B12 Deficiency

One of the reasons your body needs B12 is because it helps create red blood cells. You already know iron-deficiency anemia is one cause of an elevated A1C test. Since a deficiency in B12 often leads to anemia, it’s no wonder that it leads to high A1C readings as well. Taking B12 vitamins can also affect these levels, producing a falsely low A1C reading.

Engage with Your Blood Glucose Levels with Nutrisense

Your blood sugar levels can significantly impact how your body feels and functions. That’s why stable blood glucose levels can be an important factor in supporting overall wellbeing.

With Nutrisense, you’ll be able to track your blood glucose levels over time using a CGM, so you can make lifestyle choices that support healthy living.

When you join the program, our team of credentialed dietitians and nutritionists are available for additional support and guidance to help you reach your goals.

Ready to take the first step? Start with our quiz to see how Nutrisense can support your health.

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