Hemoglobin A1c Test

Hemoglobin is the molecule within red blood cells that carries oxygen to the body’s tissues. A small percentage of the hemoglobin has sugar attached to it, and this type of hemoglobin is known as hemoglobin A1c. The amount of hemoglobin A1c depends on the level of sugar (glucose) in the blood: the higher the blood sugar, the higher the amount of hemoglobin A1c.

• The higher the level of glucose in the blood, the higher the level of hemoglobin A1c detectable on red blood cells.
• Hemoglobin A1c levels correlate with average levels of glucose in the blood over an approximately three-month time.
• Normal ranges for hemoglobin A1c in people without diabetes are about 4% to 5.9%. People with diabetes with poor glucose control have hemoglobin A1c levels above 7%.
• Hemoglobin A1c levels are routinely used to determine blood sugar control over time in people with diabetes.
• Decreasing hemoglobin A1c levels by 1% may decrease the risk of microvascular complications (for example, diabetic eye, nerve, or kidney disease) by 10%.
• Hemoglobin A1c levels should be checked, according to the American Diabetic Association, every six months in individuals with stable blood sugar control, and every three months if the person is trying to establish stable blood sugar control.
• Hemoglobin A1c has many other names such as glycohemoglobin, glycated hemoglobin, glycosylated hemoglobin, and HbA1c.

To explain what hemoglobin A1c is, think in simple terms. Sugar sticks to things, and when it has been stuck to something for a long time, it's harder to get the sugar (glucose) off. In the body, sugar sticks too, particularly to proteins. The red blood cells that circulate in the body live for about three months before they die. When sugar (glucose) sticks to these red blood cells by binding to hemoglobin A1c, it gives the doctor an idea of how much glucose has been around in the blood for the preceding three months. The A1c meaning becomes clear when you know that it indicates the average blood sugar levels over the past three months. The standard A1c definition is that it is a lab test that shows average blood sugar levels over three months.

Hemoglobin A1c is a minor component of hemoglobin to which glucose binds. Hemoglobin A1c levels depend on blood glucose concentrations. The higher the sugar concentration in the blood, the higher the detectable hemoglobin A1c levels. At any point in time, hemoglobin A1c levels represent the average blood sugar concentrations in the person with diabetes for approximately the preceding three months. To identify between normal and prediabetic HbA1c levels, below are the interpretation ranges:

The goal for most people with diabetes is to keep HbA1c below 7%, though this may vary individually.

Other ways hemoglobin A1c may be termed include glycohemoglobin A1c, glycated hemoglobin, glycosylated hemoglobin, HbA1c, A1c, and Hb1c.

Hemoglobin A1c levels can be altered by:

• Oral or intravenous (IV) glucose intake
• Prolonged Fasting, but not for short term fasting (like the morning before the test)
• Use of insulin
• Combinations of these and other factors

The goal for people with diabetes, with their doctor's help, is to establish stable blood glucose levels resulting in hemoglobin A1c levels that are at least below 7% to reduce or stop complications of diabetes (for example, diabetic nerve, eye, and kidney diseases).

In a healthy person, the A1c level is less than 6% of the total hemoglobin. It is recommended that treatment of diabetes be directed at keeping an individual's A1c level as close to the normal range (less than 6%).

• In most labs, the normal range for hemoglobin A1c is 4% to 5.9%.
• In well-controlled diabetic patients, hemoglobin A1c levels are less than 7.0%.
• In poorly controlled diabetes, its level is 8.0% or above.

An A1c of 5.9 indicates that the person is in the prediabetic stage and further intervention is required to prevent progression to diabetes.

The average A1c level for people without diabetes is below 5.7%, whereas for people with diabetes, it should be below 7%.

Normal A1c should be less than 5.7%, which indicates healthy blood sugar control.

A dangerous level of A1c is one that rises above 9% consistently, as this increases the risk of diabetes complications such as kidney failure, vision loss or blindness, diabetic neuropathy, heart disease, and stroke.

The benefit of measuring hemoglobin A1c is that it gives a more reasonable view of what's happening over the course of time (about 3 months) to the average glucose level in the blood. Hemoglobin A1c values do not bounce up or down as much as daily finger stick blood sugar measurements.

While there are no guidelines to use hemoglobin A1c test levels as a screening tool, it gives a health care professional a good idea that someone may have diabetes if the value is elevated; however, it is used as a standard tool to determine blood sugar control in patients known to have diabetes.

The correlation between hemoglobin A1c levels and average blood sugar levels is presented in the following conversion chart:

The American Diabetes Association currently recommends an A1c goal of less than 7%, while other groups such as the American Association of Clinical Endocrinologists recommend a goal of less than 6.5%. In 2016, the ADA recommended an A1c level of 6.5% as a cutoff level to diagnose diabetes.

Studies have shown there is a 10% decrease in relative risk for microvascular complications for every 1% reduction in hemoglobin A1c. So, if a person with diabetes has an initial hemoglobin A1c level of 10.7 and drops to 8.2, though they are not yet at goal (about 6.5%), they have managed to decrease their risk of microvascular complications by about 20%. The closer to normal the hemoglobin A1c, the lower the absolute risk for microvascular complications.

The American Diabetes Association (ADA) suggests that if people with diabetes want to reduce their hemoglobin A1c levels quickly, they should get their hemoglobin A1c levels checked every three months until they reach their treatment goals.

People with diabetes who are meeting treatment goals and have stable blood control are recommended to check their hemoglobin A1c every six months according to the ADA.

Tracking hemoglobin A1c levels allows an individual and their health care professional to determine how well the person is controlling their blood sugar (glucose) levels over time. However, they are not a substitute for daily glucose monitoring. You can take an A1c test at home using a hemoglobin A1C test kit. Some at-home A1c tests may not be as accurate as tests done in the lab.

To use an HbA1c test kit at home, follow these general steps:

• Prick your finger with the lancet or needle to draw blood.
• Use the collector device to collect the blood sample.
• Insert the collector into the shaker device, which contains the testing solution.
• Shake the device to combine the sample solution with the testing solution.
• Insert the shaker into the analyzer included in the test kit.
• Wait for five minutes and then check the result.

Do you need to fast for a hemoglobin a1c test?

You don't need to fast for an HbA1c test. This test measures the blood sugar levels over the past two to three months, so recent meals or fasting doesn't compromise the result.

• What is normal hemoglobin A1c? Normal A1c levels should be less than 5.7%. This indicates healthy blood sugar levels and suggests that you do not have diabetes.
• When should I worry about my hemoglobin A1c? HbA1c values above 5.7% should be concerning, as it could indicate a prediabetic condition. It is always best to consult your physician to confirm if your results indicate any abnormality.
• What is a healthy A1c level by age? A healthy A1c level is below 5.7%, which remains the same no matter your age.