How The Test Works
The sugar in your blood is called glucose. When glucose builds up in your blood, it binds to the hemoglobin in your red blood cells. The A1c test measures how much glucose is bound.
Red blood cells live for about 3 months, so the test shows the average level of glucose in your blood for the past 3 months.
If your glucose levels have been high over recent weeks, your hemoglobin A1c test will be higher.
How Is The A1c Test Used After Diagnosis Of Diabetes
Your health care professional may use the A1C test to set your treatment goals, modify therapy, and monitor your diabetes management.
Experts recommend that people with diabetes have an A1C test at least twice a year.4 Health care professionals may check your A1C more often if you arent meeting your treatment goals.4
What Is The Cost Benefit Of Lowering A1c
Recently the ADA published analysis diabetes costs. They showed total estimated costs of $327 billion with $237 billion on direct costs and $90 billion in indirect costs.5Economic costs of diabetes continues to rise.
Data from numerous studies show that better A1C results in lower total healthcare costs.6 A study using claims data from a large health maintenance organization showed that the group of mainly type 2 patients whose A1C was lowered by 1% experienced lower total health care costs in the range of $685 to $950 less per year compared to people who had no A1C improvement.
Another analysis from a large managed care organization showed that total diabetes-related costs for people whose A1C was greater than 7% was $1,540 per patient during the 1-year follow-up. This was 32% higher than the total diabetes-related costs for people whose A1C was at or below 7%.
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Determining Your Own A1c And Eag Goals
In an ideal world, sure, we would all eat zero carbohydrates and our A1cs would be a magical 5.0. But managing diabetes is not that simple.
This means that determining that right A1c goal for you, your body, and your life as a person with diabetes is a very personal decision that you and your healthcare team decide on.
For instance, someone with a background of hypoglycemia unawareness may find a target A1c of 6.0 percent to simply be too dangerous, putting them at too much risk for severe hypoglycemia.
Someone who lives by themselves may find that sleeping with blood sugars lower than 120 mg/dL, for example, is simply too scary.
Someone who has in recovery from diabulimia and has spent the past several years with blood sugars above 300 mg/dL will need to lower blood sugar levels very gradually with the help of their healthcare team and support team. This means their A1c is going to be set at a higher target than normal, too.
To learn more about setting A1c targets and lowering your A1c , please read our comprehensive guide to lowering your A1c.
Everyone is in a different place with their diabetes management, and we all have different personal needs, challenges, and goals. And that needs to be okay. Focus on whats right for you and your current life as a person with diabetes.
How To Lower A1c
If your A1c test shows that your levels are too high, your doctor will tell you to lower it. Here are some useful tips on how to do that:
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Can My Race Or Ethnicity Affect My A1c Results
There are different kinds of hemoglobin. The most common is hemoglobin A. But some races and ethnicities have different types of hemoglobin, called hemoglobin variants.
A hemoglobin variant doesnt increase the risk for diabetes, but it can affect A1c results. Labs have different ways to do A1c tests on blood with a hemoglobin variant.
The most common variants are the:
- Hemoglobin C trait thats most commonly found in Black people, people of West African descent and people from South and Central America, the Caribbean Islands and Europe.
- Hemoglobin D trait thats most commonly found in people who live in China, India, Turkey, Brazil and some parts of Europe.
- Hemoglobin E trait thats most commonly found in Asian Americans, especially those of Southeast Asian descent.
- Hemoglobin S trait thats most commonly found in Black people and Latino Americans.
Talk to your healthcare provider about how often you should get an A1c test. Also discuss whether you might have a hemoglobin variant that could affect the results.
Last reviewed by a Cleveland Clinic medical professional on 03/30/2021.
References
Whats The Difference Between A1c And Blood Glucose Levels
February 27, 2018 by Diabetes Care
Checking your A1C as well as your blood glucose levels are things youll do when you have diabetes. Thats because they are both key markers in determining whether your blood sugar levels are within the ideal target range to keep you healthy. So whats the difference between your A1C and blood glucose level? Heres a closer look at what each one means in relation to managing your diabetes.
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Interpreting A1c: Diabetes And Hemoglobin Variants
Randie R. Little, PhD, explains what health care professionals need to know about factors that can interfere with A1C test results.
Health care professionals may use the A1C test to diagnose and manage patients with diabetes, but what are some factors that can affect the reliability and interpretation of A1C? In the second post of our Interpreting A1C blog series, Randie R. Little, PhD, discusses how hemoglobin variants can give falsely high or low readings with A1C testing methods, and how this can lead to the over-treatment or under-treatment of diabetes.
Q: What are hemoglobin variants and how can they affect the reliability of the A1C test used to diagnose and manage diabetes?
A: Normal human hemoglobin is made up of about 98% hemoglobin A . Some people have both HbA and another kind of Hb, such as hemoglobin S, C, D or E. These less common forms of hemoglobin are called hemoglobin variants, or hemoglobinopathies.
Some hemoglobin variants can affect some HbA1c methods, but not all of them. For instance, certain variants can cause falsely high or low A1C test results depending on the method used. The A1C blood test, also called the hemoglobin A1C test, HbA1c, or glycated hemoglobin test, reflects a persons average blood glucose levels for the past 3 months.
Q: What are some common types of hemoglobinopathies?
A: There are hundreds of hemoglobin variants, but there are four that are the most common:
Using The Gmi To Estimate Your A1c: How Accurate Is It
GMI provides an estimated A1C level based on continuous glucose monitoring data and can avoid some of the limitations of A1C tests. A recent study compared actual A1C levels with GMI to see how the two compared in the real world.
The A1C test is commonly used to assess a persons glucose management. A higher A1C is associated with higher glucose levels and more health complications. Although long considered a gold standard in diabetes care, the A1C has a huge limitation: its just an average. A person could spend a lot of time with low blood sugar levels and a lot of time with high blood sugar levels, yet have an A1C under 7%, which is the target for most people with diabetes. You can learn more about the limitations of A1C here.
For those who wear a continuous glucose monitoring system , the glucose management indicator essentially estimates A1C in fact, it used to be called an estimated A1C. Without the need for a blood draw, it takes the average of your glucose readings and uses a formula to estimate what your A1C is expected to be. To calculate GMI you should have at least 14 days of data.
Your glucose management can also be measured by Time in Range , Time Below Range and Time Above Range . Generally, a Time in Range of 70% or greater is equivalent to an A1C of 7% or less. This data is quite useful to see if you are meeting your glucose targets or if you need to adjust your diabetes treatment plan. Learn about TIR and how it can help your diabetes management here.
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Summary A1c Vs Glucose
A1c and glucose are two tests that will help doctors to diagnose diabetes in a patient. A1c measures the glucose that is bound to hemoglobin in red blood cells. Glucose test measures the glucose concentration in milligrams of glucose per deciliter of blood. Importantly, the A1c test does not require fasting, but glucose test requires fasting overnight. Moreover, a glucometer is used to measure blood glucose, while glucometer cant tell your A1c. HbA1c is the main test used to manage diabetes since it measures how the body is managing blood sugar over time, usually the last 23 months. However, doctors use both methods to diagnose and confirm diabetes. Thus, this concludes the discussion on the difference between A1c and glucose.
Reference:
1. Sacks, David B. A1C Versus Glucose Testing: A Comparison. Diabetes Care, American Diabetes Association, 1 Feb. 2011, Available here.2. MacGill, Markus. The A1C Test: Uses, Procedure, and Target Levels. Medical News Today, MediLexicon International, 27 Mar. 2019, Available here.
Image Courtesy:
2. Blood Glucose Testing By David-i98 via Commons Wikimedia
What Is The Hba1c Why Is It So Important
The abbreviation HbA1c stands for Glycosylated Haemoglobin and its a test that usually involves taking blood from your vein. There are some testing machines that can do your HbA1c from a finger prick but generally your doctor will refer you to a pathology service to have the test done.
The HbA1c reflects your average blood glucose level over the last 10-12 weeks and it is recommended that you have it done at least every 12 months, although you may be advised to have it done more often such as 3 to 6 monthly. A HbA1c test helps you see how well you are looking after your diabetes.
The HbA1c develops when haemoglobin, a protein within red blood cells that carries oxygen throughout your body, joins with glucose in the blood, becoming glycated. For people with diabetes this is important because the higher the HbA1c, the greater risk of developing diabetes related complications.
Red blood cells survive in your body for 8-12 weeks before they are renewed. This is the reason HbA1c tests are done at a minimum of 3 months apart.
The results of your HbA1c test are shown in 2 ways on the pathology report. They are expressed as a percentage or as a value in mmol/mol.
Mmol/mol has been added to your pathology result because it is the international way of measuring HbA1c.
The table below shows a comparison of HbA1c and blood glucose levels:
| HbA1c % |
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What Is The Difference Between A1c And Glucose
Hemoglobin A1c test measures the percentage of glucose bound to red blood cells in the blood, while glucose test measures the milligrams of glucose per deciliter of blood. So, this is the key difference between A1c and glucose. Blood sugar meters cant check for hemoglobin A1c, but they can check blood glucose.
Moreover, glucose tests require fasting before the test, while the A1c test does not require fasting before the test. Thus, this is another difference between A1c and glucose. In an A1c test, it is necessary to take some blood and send it to the laboratory for assessment. But, in glucose test, it is necessary to squeeze a drop of blood onto the test strip and put the strip into the monitor. Furthermore, A1c measures in percentage while glucose test measures blood sugar in mg/dL.
Below infographic summarizes the difference between A1c and glucose.
What If Your Test Says You Have A Higher Level Of A1c But You Do Not Have Diabetes
High A1c levels do not always necessarily mean that you have diabetes. The NIH reports that high A1c causes include blood disorders like anemia, as well as liver disease, kidney failure, and sickle cell disease.
If your A1c levels are high, your doctor may perform a blood glucose test to diagnose or rule out diabetes. If you do not have diabetes, your doctor may order another type of lab test to identify the root cause of high A1c.
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What If My Hba1c Is Normal But My Glucose Is Above Optimized
Sleep deprivation
Theres evidence that poor sleep patterns impair glucose metabolism. People on restricted sleep demonstrate worsened insulin response to food, resulting in higher blood glucose spikes. In one study, sleep-deprived people had higher glucose and insulin levels after consuming breakfast compared to those who slept a healthy eight hours. Other studies confirm this findinginsulin resistance is more common in people deprived of sleep.
Stress
The body releases a steroid hormone called cortisol to activate our “flight-or-fight” responses to counteract acutely stressful situations. Cortisol stimulates the release of blood glucose by breaking down its storage form, glycogen. If youve experienced a stressful week, good chances are your blood sugars may be slightly higher than normal.
Food
Because glucose fluctuates after meals, we recommend fasting for a full 12 hours prior to getting a blood test for an accurate reading. This means water only, not even black coffee. People react differently to coffee so we suggest to err on the side of caution and stick to just water.
How Is The A1c Test Used To Diagnose Type 2 Diabetes And Prediabetes
Health care professionals can use the A1C test alone or in combination with other diabetes tests to diagnose type 2 diabetes and prediabetes. You dont have to fast before having your blood drawn for an A1C test, which means that blood can be drawn for the test at any time of the day.
If you dont have symptoms but the A1C test shows you have diabetes or prediabetes, you should have a repeat test on a different day using the A1C test or one of the other diabetes tests to confirm the diagnosis.2
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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 doesnât 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.
Your A1c Target Is Your Own
You are unique and you need advice based on your own set of circumstances. If someone who hears your A1C says, Your A1C level should be x, y, or z. Your response can be: I am working with my doctor on reaching my own safe diabetes target, and it has been customized for my condition.
A1C targets often change over time, sometimes decreasing and sometimes increasing. It all depends on the person and circumstances. Dont compare yourself or your child to others. Know your goals and be clear, persistent and honest in your approach to managing diabetes.
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Why Do We Test A1c
Also called hemoglobin a1c or Hba1c, an A1C test is often used to diagnose diabetes initially and then to ensure youre keeping your blood sugar levels in check over an extended period of time. Given that the average red blood cell lives for several months, this test determines your average blood sugar levels over a two- to three-month period.
Which Is More Important: The A1c Test Or Fasting Glucose Level
With all due respect to the other people who have answered, Neither as both are IMO as much different as they are equally important for both the patient and the physician. While the A1C test, which measures an average glucose level over a period of about 3 months, to wit : Glycated hemoglobin is a form of hemoglobin that is measured primarily to identify the three-month average plasma glucose concentration. The test is limited to a three-month average because the lifespan of a red blood cell is four months. Wikipedia and the fasting glucose level just gives you a snapshot of a single moment in time, after consuming No Liquids for 8-hours before the blood draw though its also 810 hrs in some journals, and Im not so sure if 1012+ hours necessarily makes that much more difference. Frequently, if one tests somewhat high for 2 or more fasting levels, or the levels are rising, then the physician may very well order the A1C Not only can the A1C help diagnose diabetes, but many physicians may use it to also use it post diagnosis to monitor how well the diabetic patient is participating in controlling their diabetes. Nat, just my diabetic $.02 worthContinue reading > >
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How Often Do I Need An A1c Test
This calculator only estimates how the A1C of someone who self-monitors quite frequently might correlate with their average meter readings. But many factors can affect blood glucose, so its critical to have your A1C checked by your doctor regularly.
The ADA recommends an A1C test at least 2 times a year for those who are in good control. For those who have changed their therapy or who are not in good control and not meeting glycemic goals, an A1C test is recommended quarterly. Your doctor will help you decide whats right for you.1