This page helps you to understand blood test results for Haemoglobin A1c (HbA1c) and gives you the reference range to determine if your lab test results mean that you have high, low or normal Haemoglobin A1c (HbA1c) levels.
We outline the risk factors associated with both raised and lower Haemoglobin A1c (HbA1c) levels.
Reference Ranges for Haemoglobin A1c (HbA1c):
|US Conventional Units||%||4-5.6||5.7-6.4||<4 or > 6.4|
|Standard International Units||%||4-5.6||5.7-6.4||<4 or > 6.4|
What is Haemoglobin A1c (HbA1c)
HbA1c level reflects the mean glucose concentration over approximately 8-12 weeks depending on the individual, and therefore provides a much better indication of long-term glycemic control than blood and urinary glucose determinations. Diabetic patients with very high blood concentrations of glucose have from 2 to 3 times more HbA1c than normal individuals .
Function of Haemoglobin A1c (HbA1c)
Specifically, the HbA1C test measures what percentage of your hemoglobin — a protein in red blood cells that carries oxygen — is coated with sugar (glycated).
Risk factors associated with Haemoglobin A1c (HbA1c)
Diabetes – There are a few different conditions that may disrupt the balance between glucose and the pancreatic hormones, resulting in high or low blood glucose. The most common cause is diabetes. Diabetes is a group of disorders associated with insufficient insulin production and/or a resistance to the effects of insulin. People with untreated diabetes are not able to process and use glucose normally. Those who are not able to produce any or enough insulin (and typically have diabetes autoantibodies) are diagnosed as having type 1 diabetes. Those who are resistant to insulin and may or may not be able to produce sufficient quantities of it may have prediabetes or type 2 diabetes .
Gestational Diabetes – Some women may develop gestational diabetes, which is hyperglycemia that occurs only during pregnancy. If untreated, this can cause these mothers to give birth to large babies who may have low glucose levels. Women who have had gestational diabetes may or may not go on to develop diabetes .
Chronically high blood glucose levels can cause progressive damage to body organs such as the kidneys, eyes, heart and blood vessels, and nerves. Chronic low blood sugar can lead to nerve damage .
Notable variations by demographic group
Recently, racial and ethnic differences in the relationship between HbA1c and blood glucose have been reported. Although the reasons for racial and ethnic differences remain unknown. Factors such as differences in red cell survival, extracellular-intracellular glucose balance, and non-glycemic genetic determinants of hemoglobin glycation are being explored as contributors. Until the reasons for these differences are more clearly defined, HbA1c should be used in combination with traditional glucose criteria when screening for and diagnosing diabetes .