Understanding HbA1c Test: The Purpose and Procedure of this Vital Test

Glycated hemoglobin (HbA1c) analysis of blood gives information about a person's average blood glucose levels over the preceding two to three months, correlating with the lifespan of red blood cells. This test can be a useful tool in diagnosing diabetes because it is a simple, fast, and accurate way to obtain results instantly. It's amongst the confirmatory tests as well as a standard of care (SOC) for diagnosing and monitoring diabetes, particularly type 2 diabetes.

Depending on the diabetic history of patients, whether they take tablets or receive long-term or short-term insulin shots, and various other factors, different diabetes patients have different HbA1c levels. Hyperglycaemia (high blood glucose level) is a symptom of type 2 diabetes mellitus (DM), which is caused by impaired production or availability of insulin for the cells.

In addition to being a valuable indicator of long-term diabetic control, HbA1c is also a reliable indicator of lipid profile. For this reason, tracking glycemic control with HbA1c may also help to identify diabetes patients who are more likely to experience heart problems. According to studies, there exist inverse associations between HbA1c and good cholesterol (high-density lipoprotein cholesterol), and direct associations between HbA1c and bad cholesterol (triglycerides, cholesterol, and low-density lipoprotein cholesterol). In individuals who are highly susceptible to diabetes, an elevated HbA1c level has been found to be a significant risk factor for heart diseases and stroke.

The HbA1c test may be used more often as a diagnostic and prognostic tool as the global diabetes epidemic advances, improving patient care by providing accurate clinical results. Let’s know more about this vital test in the following article.

What is the HbA1c Test?

The hemoglobin A1c test determines the amount of glucose or blood sugar that has circulated in your bloodstream over the past three months. This test serves as a marker for long-term glucose control and can be used to diagnose diabetes or monitor its control or progress.

Diabetes is characterized by high blood glucose levels. Glucose comes from our food and is used by our cells for energy generation. Insulin is a hormone that facilitates the uptake of glucose by your cells. Our cells either can't utilize insulin effectively or our body fails to produce enough insulin if we have diabetes. Consequently, blood sugar levels rise because glucose is unable to enter your cells.

What is the Purpose of the HbA1c Test? 

• Screening Prediabetes or diabetes: Before you notice any symptoms, your doctor might want to rule out any underlying medical conditions if you are over 40 and obese, overweight, or  at high risk of developing diabetes.
• Diagnosis of Prediabetes or Diabetes: If you exhibit signs of diabetes or have symptoms, your doctor might recommend tests like hemoglobin A1c. Extreme fatigue, tingling or loss of feeling in the hands and feet, frequent urination, excessive thirst, and blurred vision are some symptoms of diabetes.
• Monitoring Diabetes Progression or Control: Your physician may prescribe this test to you at least twice a year if you have been diagnosed with diabetes. This enables your doctor to modify your treatment plan and reduce the likelihood of health issues by getting an insight into how well your blood glucose has been managed in the months in between appointments.

Principle Behind HbA1c Test

Glycated hemoglobin is known as HbA1c. Blood cells contain a protein called hemoglobin (Hb), which is responsible for carrying oxygen throughout the body. Blood and hemoglobin are combined to form HbA1c (also known as "glycated" hemoglobin).

Blood glucose binds to the protein called hemoglobin found in red blood cells. More of your hemoglobin will become encased in glucose as the blood glucose levels rise. The hemoglobin and glucose are bound as long as red blood cells are alive. The lifespan of red blood cells is three months.

What Does the HbA1c Test Measure?

HbA1c Test measures and determines the percentage of the red blood cells with glucose-coated hemoglobin. It provides the average value of the previous three month's blood glucose levels corresponding to the lifespan of red blood cells.

HbA1c Test Preparation 

There are no special preparations required before your Hb A1c test. However, make sure to discuss with your doctor any more tests that might be performed on the same visit, as some of them might require you to fast, alter your diet, or make other preparations in advance.

HbA1c Test Procedure

In order to increase blood flow and put pressure on your vein during a hemoglobin A1c test that requires a blood sample from a vein, the phlebotomist may first tie a band at the top of your arm beneath your shoulder. 

• A tiny needle will be inserted into the vein in your elbow pit after the skin surrounding it has been thoroughly cleaned with a sterile wipe. 
• A tube fastened to the needle will be used to collect your blood sample.
• You may experience slight discomfort or stinging sensation when the laboratory technician inserts or removes the needle. 
• This process will take approximately five minutes or less. 
• A lancet will be used to prick the tip of your finger until a drop of blood appears if your hemoglobin A1c test requires a fingerstick blood sample. 
• A small amount of pain may be experienced when your finger is pricked. 
• The blood sample will be mixed with a specific ingredient that prevents the unwanted blood clotting in the sample. 
• Then the sample is placed within a cartridge for storage.

HbA1c Test Result Interpretation

HbA1c Test results are generally obtained within a day. The results of your fingerstick hemoglobin A1c test will be available right away. Results of the hemoglobin A1c test are represented in percentages. The reference ranges and the context of your general health are used by doctors to interpret the hemoglobin A1c test results. Depending on whether you are using the test to screen for diabetes or to diagnose it, the interpretation of your results will vary. Following are the reference ranges:

• Normal: less than 5.7 %
• Prediabetes: between 5.7 — 6.4 %
• Diabetes: 6.5 % or above

Conclusion

Your doctor or another healthcare professional may offer you guidance on long-term monitoring and management of diabetes if you are diagnosed with the condition. To monitor your diabetes with the test, you and your doctor will set a target Hb A1c number. This target will be unique to you and may vary as your diabetes treatment progresses depending on your age, previous blood glucose control experience, and any potential complications from your diabetes. Your doctor will also take into account any history of low blood sugar to prevent hypoglycemic attacks and associated complications while making your treatment plan.

Take control of your blood sugar now. Get expert advice on your diabetes care and HbA1c test. 

Frequently Asked Questions (FAQs)

Q1: What affects the HbA1c test results?
A: Elevated HbA1c can occur due to iron deficiency, inadequate vitamin B12 levels, reduced red blood cell formation. Reduced HbA1c can occur due to reticulocytosis (abnormal blood cell formation) and chronic liver disease. It can also occur due to  iron, vitamin B12, and/or erythropoietin intake.

Q2: What is the HbA1c safe limit?
A: An HbA1c test result must be less than 5.7% (safe limit) in order to be considered normal or in the non-diabetic range. A person can be diagnosed with diabetes if their HbA1c is 6.5% or higher. Person having test results between 5.7% and 6.4% is considered prediabetic.

Q3: Which medicines interfere with HbA1c test results?
A: Medication that results in mild haemolysis but does not result in anemia may affect the precision with which an A1C measurement is made. Antiretroviral medications, dapsone, sulfasalazine, and ribavirin are reportedly examples of such medications.