HbA1c blood test also known as glycated hemoglobulin test or glycohemoglobin test or hemoglobin A1c test or A1C is to determine 3-month average blood sugar / glucose level.
Hemoglobulin is iron containing protein in red blood cells which helps to transport gases like Oxygen and Carbon Dioxide from Lungs to other body parts and vice versa.
On an average every healthy individual has 12-20 grams hemoglobulin per 100 ml of blood.
It is pertinent to mention that all other tests measure concentration of sugar / glucose in blood but HbA1c test measures concentration of hemoglobulin attached with sugar/ glucose molecule in blood.
Why HbA1c blood Test is limited to 3-month average blood sugar level?
As stated above protein called hemoglobulin is part of red blood cells.
The “heme” compound of hemoglobulin is prime reason for red color of blood and plays important role in transport of oxygen and carbon dioxide gases to various organs through blood.
The average life span of red blood cells is about 100-115 days and varies individually. For this reason 3 months is representative period to measure glycated hemoglobulin in blood sample.
What is HbA1c or glycated hemoglobulin or glycol hemoglobulin?
Glycation is attachment of glucose to protein. In this case glucose is attached to hemoglobulin and leads to generation of HbA1c or glycated hemoglobulin or glycohemoglobin.
It is normal process and is directly proportional to concentration of glucose in blood stream.
Initially with normal amount of glucose in blood HbA1c is within normal range of 5.7 % but as concentration of calorie in form of glucose or mainly carbohydrates increase concentration of HbA1c also increases leading to prediabetes at 5.7% to 6.4% and diabetes above 6.4%.
Prolonged hyperglycaemia is one of most important trigger for HbA1c.
What above normal HbA1c blood test results mean for individual?
Above normal range or higher HbA1c level mean there is higher amount of glucose bound to hemoglobulin. This condition leads to increase in viscosity of blood causing impaired blood flow in blood vessels.
Over the long period of time this may lead to high blood pressure condition for individual. This is also due to stiffening of collagen inside blood vessels.
Free radicals released from hemoglobulin causes clumping and is associated with inflammation.
Further it may also lead serios complication and damage to retina of eye i.e retinopathy, damage to kidney i.e nephropathy, i.e damage to nerves associated to spinal cord and brain i.e neuropathy and diseases of Heart i.e cardiovascular.
Who is in need of HbA1c test?
Following people are in need of HbA1c:
- People who are obese and overweight.
- People who suffer from high blood pressure.
- People who have prediabetes.
- People planning baby.
- People with family history of Diabetes.
- Women having polycystic ovarian syndrome (PCOS).
- People who show general symptoms of diabetes like
Following are the general symptoms in above cases:
- Feeling thirsty
- Feeling hungry
- Frequent urination
- Feeling frequently tired.
- Blurred vision
- Sores take longer to heal
- Increased Ketone levels.
How is HbA1c test conducted?
HbA1c test involves collection of blood sample from vein of arm using needle or by pricking finger using lancet. Blood sample generally give result in few hours while finger prick gives result instantly.
What are the factors affecting HbA1c test?
Following are the factors affecting results of HbA1c Test.
- Blood Transfusion or Blood Loss.
- Kidney Disease
- Liver Disease
What are results of HbA1c test and what is co-relation between HbA1c level and average glucose level?
Generally higher the average glucose level for longer period of time higher is the HbA1c level as both are directly proportional.
Please refer the chart below.