“Did You Know?” is a blog contributed by T1DE families. It’s easy, pick a T1D related subject and provide a Q and A. We hope that by participating, you and all of our families will have fun and learn something along the way! The information provided on T1DE is not professional medical information. Always consult with your physician before making any changes to your medical care. If you have any comments on this blog or would like to contribute a subject, please email us!
March 2013 – Glycated Hemoglobin by Jordon
What is the Glycated Hemoglobin test?
Commonly known as Glycohemoglobin (HbA1c, A1C), this is the standard test used in the medical community to diagnose and track a patients control of their diabetes for both type I and type II diabetes. The results provides an estimate of the patients average blood sugar over the last few months.
How can the test determine what your average glucose has been over the last few months?
In general, hemaglobin in the blood is constantly being made and these red blood cells live in the body for only a limited time, approximately 3-4 months. Glucose in the blood will bind to the new hemoglobin cells. The A1C test is a ratio of the hemoglobin cells that have glucose verses those that do not. From that ratio, the average blood sugar can be estimated. The higher the A1C percentage, the higher the average blood sugar. Since the hemoglobin cells life cycle is approximately three months, the ratio is essentially a running blood sugar average over that life cycle.
What is a normal A1C for a non diabetic?
The medical community considers a “normal” a1c is a range from 4.5-6% corresponding to a average blood sugar of ~80-120 mg/dl. 5.7 and 6.4 percent is considered prediabetes, which indicates a high risk of developing diabetes. However some experts believe that a truly normal blood sugar is ~83 mg/dl or an A1C ~4.3% and children have found to run even lower.
What is a normal A1C for a type I diabetic?
This is a trick question! It is whatever you want it to be! There is no reason that a diabetic can not have near perfect blood sugar control as good or even better than a “non-diabetic”. There are many type I diabetics that have A1C well below 5%! Keep in mind, if ~83 mg/dl is truly a normal blood sugar, then 120 mg/dl is almost 50% over the normal so 1 percentage point in A1C is very very significant!
Is the A1c test a substitute for checking sugars daily?
For a type I diabetic, absolutely not!!! The A1C test is a qualitative measurement that can be used to compare against daily readings (or lack of!!!) but is not an instantaneous value of blood glucose. Instantaneous readings can only be obtained from your glucose meter and finger prick! Normally 5-8 times a day.
Can the A1C test results be deceiving?
YES! If you have many lows and/or highs during the day, your average may be good but in reality those peaks and valleys (i.e. roller-coasters) skew your average. There are a number of other factors that can skew the test results including iron levels, etc. Also keep in mind that those swings cause nerve damage so a good A1C may not be as good as you think. Also the accuracy of your meter makes a huge difference in comparing your average readings from your meter to the A1C results. Not all glucose meters are equal!!! There is data out there to see how accurate your meter is and this is a whole separate topic!
Why should I care what my A1C is?
The DCCT was a landmark study that showed how blood sugar control contributed to diabetic complications. The higher your average glucose, the sooner and more serious the complications become. Although your doctor may say you are in control with a A1C less than 7%. don’t be fooled.
The Good News:
On the bright side, type I diabetics have been able to achieve consistent A1C below 5% and reverse some early diabetic complications. Even if you have complications now, it is not too late. It’s hard work but people do it!