What is the A1C Test?
Since the 1980s, the A1C test has become a common test used to diagnose those with type 1 and type 2 diabetes. If you are currently living with diabetes, your doctor may routinely perform this test to see how well you are managing your condition.
The A1C test provides an accurate reading of blood glucose levels despite the time of day, hormonal changes, and level of activity.
Hemoglobin is a protein molecule in red blood cells that transports oxygen. The A1C test measures the percentage of hemoglobin in your blood that is coated with sugar (glycated).
If your test results are displaying a high A1C level, this is interpreted as poor blood sugar management and a potential risk of diabetes complications.
The A1C test is also known as the glycated hemoglobin test, glycosylated hemoglobin test, hemoglobin A1C test, and HbA1.
This common diabetes test is performed like any other standard blood test. A sample of blood is taken through a needle and then sent to a lab for testing.
Who should get the A1C Test?
All individuals with diabetes should have routine testing done. Such testing not only assesses the short-term management of the condition but also the long-term.
Doctors may modify a patient’s diabetes treatment plan based on their A1C levels and further examine results for complications like kidney disease, blindness, heart disease, and stroke.
If you are age 40 or older, you should receive the A1C test every 3 years. If you have diabetes then you should receive this test more frequently.
Some risk factors for diabetes include:
- If you are overweight,
- Have a parent or sibling with diabetes
- Polycystic ovary syndrome (PCOS)
- High blood pressure
- High cholesterol
- Have a family history of gestational diabetes
- Have psychiatric disorders (bipolar disorder, schizophrenia)
Consult with your doctor or pharmacist if you are unsure whether you require this test or how often you should take the A1C test.
Why is an A1C test performed?
The hemoglobin A1C test is performed by doctors and health care providers to:
- Diagnose type 1 and type 2 diabetes. Your physician will look at the results of the A1C test before determining a diagnosis. Sometimes the A1C test is used alone or in conjunction with other tests such as a blood sugar test or fasting.
- Diagnose prediabetes. Those who have prediabetes are put at a higher risk of developing diabetes.
- Monitor a patient’s treatment plan. From the results, patients receive their baseline level which is used to compare against future results to gauge progress and how the treatment is adjusted.
The frequency of A1C testing depends on the severity of an individual’s diabetes, how well they have managed their diabetes, and their treatment plan.
The frequency of an A1C test may be suggested based on the following:
- Once per year for those with prediabetes
- Twice per year if blood sugar levels are within a safe range and you don’t use insulin
- Four times a year if blood sugar levels are not within a safe range and you take insulin
- More frequent if you are just starting a new medication and/or treatment plan
How to Prepare for an A1C Blood Test
For an A1C test, you don’t need to fast beforehand. You can eat and drink normally.
A blood sample may be extracted by drawing blood from a syringe or pricking blood from your fingertip using a lancet. The blood sample is then sent to a lab for testing.
If your doctor tests blood sugar levels using a lancet, this isn’t to provide a diagnosis but to monitor your treatment plan.
The A1C level test results are reported as a percentage. If the results show a higher percentage, this translates to higher blood glucose levels. The following percentages below can mean the following:
- Normal – Below 5.7%
- Diagnosed Prediabetes – Between 5.7-6.4%
- Diagnosed Diabetes – 6.5% or higher
Doctors may modify a patient’s treatment based on the results and their current health.
A1C test limitations
The accuracy of an A1C test may be affected by the following:
- Recent blood transfusion
- Hemoglobin variants
- Anemia/insufficient blood cells
- Heavy blood loss
A blood glucose meter or blood monitoring system may be part of your treatment plan to show blood sugar levels at a certain time of testing. A doctor, nurse, or health practitioner may provide instructions on how to test and how often you should test your blood sugar levels.
By using the previously mentioned devices, blood sugar levels can be measured by looking at milligrams of sugar per deciliter (mg/dL) or millimoles of sugar per liter (mmol/L).
Results can be affected by various factors including the type of food, time of meals, exercise, and other factors.
Testing and understanding your blood glucose readings can help you make certain lifestyle choices such as food and exercise.
The correlation between your A1C levels and blood sugar levels is usually as follows:
|A1C level||Estimated average blood sugar (glucose) level|
|6%||126 mg/dL (7 mmol/L)|
|7%||154 mg/dL (8.6 mmol/L)|
|8%||183 mg/dL (10.2 mmol/L)|
|9%||212 mg/dL (11.8 mmol/L)|
|10%||240 mg/dL (13.4 mmol/L)|
|11%||269 mg/dL (14.9 mmol/L)|
|12%||298 mg/dL (16.5 mmol/L)|