Blood Glucose & A1C: What Does It All Mean?

Glycemic control is the assessment of blood glucose control in a person with diabetes. Daily self-monitoring of blood glucose (SMBG) and periodic testing of A1c (hemoglobin A1c, HbA1c) are currently the two primary methods for assessing both short term and long term glycemic control, respectively.

Blood Glucose Monitoring

What is blood glucose monitoring?

Self-monitoring of blood glucose (SMBG) is done by using a home blood glucose meter. A small amount of blood is added to a test strip that has been inserted into the meter. The meter measures the amount of glucose in the blood. Test results are available within a few seconds.

Why is blood glucose monitoring important?

SMBG allows you to see on a day-to-day basis how food, exercise and medication impact your blood glucose levels. Keeping a written blood glucose log (or using an application on your phone) over a period of 1- 2 weeks can help reveal patterns. Your physician and/or diabetes educator can use this information to recommend changes to your current diabetes regimen.

How often should blood glucose be checked?

The frequency of blood glucose monitoring will depend on how your diabetes is currently managed (i.e. diet/exercise, oral medication, insulin). Work with your physician to determine how often you should check your blood glucose. The American Diabetes Association Standards of Medical Care in Diabetes 2017 recommends the following:

  • “Most patients using intensive insulin regimens (multiple-dose insulin or insulin pump therapy) should perform self-monitoring of blood glucose (SMBG) prior to meals and snacks, at bedtime, occasionally postprandially (after meals), prior to exercise, when they suspect low blood glucose, after treating low blood glucose until they are normoglycemic, and prior to critical tasks such as driving.”1
  • “When prescribed as part of a broad educational program, SMBG may help to guide treatment decisions and/or self-management for patients taking less frequent insulin injections or non-insulin therapies.”1

What are blood glucose targets?

The American Diabetes Association recommends the following blood glucose targets:

  • Fasting and pre-meal: 80-130 mg/dL
  • 1-2 hours after a meal: < 180 mg/dL
  • Important note: blood glucose targets may be different if you are elderly or have a more complex medical history.

A1c test

What is the A1c test?

The A1c test is a blood test that assesses blood sugar control over the last 3 months.

  • You do not need to fast prior to having the A1c test done
  • It can be done at your doctor’s office or at a laboratory
  • The A1c test assesses how much glucose has attached to hemoglobin. Hemoglobin is the oxygen carrying molecule in the red blood cells. Red blood cells live for approximately three months; making the A1c test a good assessment of blood glucose levels over the past 3 months.2
  • The A1c test is reported as a percentage. The higher the A1c percentage, the higher blood glucose levels have been during the previous 3 months.2

Why is the A1c test important?

  • The A1c test “…has strong predictive value for diabetes complications”.1
  • Measuring the A1c “……. every 3 months determines whether patients’ glycemic targets have been reached and maintained.”1

What is the target A1c?

The American Diabetes Association Recommends the following A1c target (for non-pregnant adults):

  • 7% or less 1

Your physician may recommend at different A1c target if you are: pregnant, under age 18, elderly, have microvascular complications, or a history of severe hypoglycemia. 1

How often should A1c be checked?

The American Diabetes Association 2017 Standards of Medical Care in Diabetes recommends the following:

  • Patients meeting treatment goals: test A1c, at minimum, twice per year.1
  • Patients not meeting treatment goals or a recent change in therapy: test A1c every 3 months. 1

Additional Pointers:

  • A diabetes educator can show you how to use a blood glucose meter. Accurate blood glucose results are dependent on proper technique.
  • Certain medical conditions and medications may cause test (blood glucose and/or A1c) results to be either falsely high or falsely low.
  • It is important to keep your physician informed of any changes in your medical history and to provide a complete list of medications you are currently taking (including dietary and herbal supplements).
This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The Type2Diabetes.com team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.
View References
  1. American Diabetes Association. Glycemic Targets. Sec. 6. Standards of Medical Care in Diabetes- 2017. Diabetes Care 2017; 40(Supp. 1): S48-S56.
  2. The A1C Test & Diabetes. National Institute of Diabetes and Digestive and Kidney Diseases https://www.niddk.nih.gov/health-information/diabetes/overview/tests-diagnosis/a1c-test. Accessed January 18, 2018.
  3. Radin M. Pitfalls in Hemoglobin A1c Measurement: When Results may be Misleading. J. Gen Intern Med. 2014; 29(2): 388-394. doi:  10.1007/s11606-013-2595-x.

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