Hemoglobin A1c (HbA1c) Test for Diabetes

What is a Hemoglobin A1c (Average Blood Sugar) Test?

The Hemoglobin A1C Test  is also called HbA1c, glycated hemoglobin test, or glycoslated hemoglobin test is a common blood test used to diagnose type 1 and type 2 diabetes to determine how well your diabetes is being controlled. 

According to American Diabetes Association, the test result of A1c reflects your average blood sugar level for the past two to three months. Specifically, the A1C test measures what percentage of your hemoglobin (a protein in red blood cells that carries oxygen) is coated with sugar (glycated). The higher your A1C level, the poorer your blood sugar control and the higher your risk of diabetes complications. 

Why Hemoglobin A1c Test  is Done?

Based on the international committee of experts from the European Association for the Study of Diabetes, American Diabetes Association, and International Diabetes Federation stated that they recommends the A1C test as the primary test used to diagnose prediabetes, type 1 diabetes and type 2 diabetes.

A1C test can help you manage your diabetes:
  • to determine if your treatment plan is working properly
  • to confirm self-testing results or blood test results by the doctor.
  • to show you how healthy choices can make a difference in diabetes.
How to Prepare A1c Test?

A1c Test is a quite simple blood test. You just eat and drink normally before the test.

Expect your the A1c test

During the test, the health care team practitioner simply takes a sample of blood by inserting a needle into a vein in your arm or pricking the tip of your finger with a small, pointed lancet. The blood sample is sent to a lab for analysis. You can return to your usual activities immediately.

The Results

After the blood analysis, the results conclude for someone who doesn't have diabetes, a normal A1C level can range from 4.5 to 6 percent. Someone who's had uncontrolled diabetes for a long time might have an A1C level above 8 percent.

When the A1C test is used to diagnose diabetes, an A1C level of 6.5 percent or higher on two separate tests indicates you have diabetes. A result between 5.7 and 6.4 percent is considered prediabetes, which indicates a high risk of developing diabetes.

For most people who have previously diagnosed diabetes, an A1C level of 7 percent or less is a common treatment target. Higher targets may be chosen in some individuals. If your A1C level is above your target, your doctor may recommend a change in your diabetes treatment plan. Remember, the higher your A1C level, the higher your risk of diabetes complications.

Here's how A1C level corresponds to average blood sugar level, in milligrams per deciliter (mg/dL) and millimoles per liter (mmol/L):

A1C level        Estimated average blood sugar level
5 percent        97 mg/dL (5.4 mmol/L)
6 percent        126 mg/dL (7 mmol/L)
7 percent        154 mg/dL (8.5 mmol/L)
8 percent        183 mg/dL (10.2 mmol/L)
9 percent        212 mg/dL (11.8 mmol/L)
10 percent        240 mg/dL (13.3 mmol/L)
11 percent        269 mg/dL (14.9 mmol/L)
12 percent        298 mg/dL (16.5 mmol/L)
13 percent        326 mg/dL (18.1 mmol/L)
14 percent        355 mg/dL (19.7 mmol/L)

What are the limitations?

Although the A1C test is an important tool, it can't replace daily self-testing of blood glucose for those who need it. A1C tests don't measure your day-to-day control. You can't adjust your insulin on the basis of your A1C tests. That's why your blood sugar checks and your log of results are so important to staying in effective control.






Source & References:
    1. A1c Test - mayoclinic.com Retrieved last March 3, 2013
    2. Living with Diabetes  - diabetes.org. Retrieved last March 3, 2013 
    3. The Hemoglobin A1c (HbA1c) Test for Diabetes - webmd.com Retrieved last March 3, 2013 
    4. Image source: http://www.dlife.com/diabetes/export/pics/dLife_Images/A1C_Levels_p1.jpg. Retrieved last March 3, 2013


    Oral Glucose Tolerance Test (OGTT)

    What is Oral Glucose Tolerance Test?

    The oral glucose tolerance test (OGTT), also known as the glucose tolerance test, is a lab test to how your the body’s ability to metabolize glucose, or clear it out of the bloodstream. In this procedure the The patient is asked to take a glucose drink and their blood glucose level is measured before and at intervals after the sugary drink is taken. The test can be used to diagnose diabetes, gestational diabetes  or prediabetes.

    The test is a more substantial indicator of diabetes than finger prick testing

    Why OGTT is Done?

    According to webmd.com the Oral Glucose Tolerance Test is done to:
      • Check pregnant women for gestational diabetes. You have an increased chance of developing gestational diabetes if you:
        • Have had gestational diabetes during a previous pregnancy.
        • Have previously given birth to a baby who weighed more than 9 lb (4.1 kg).
        • Are younger than age 25 and were overweight before getting pregnant.
      • Diagnose prediabetes.
      • Diagnose Insulin resistance, and
      • Reactive hypoglycemia
      How to Prepare the Test?

      For those who taking the test to diagnose diabetes or prediabetes, you must need first to prepare before performing the diagnostic test:
      • You must eat a balanced diet that contains at least 150 grams (g) of carbohydrate per day for 3 days before the test. Fruits, breads, cereals, grains, rice, crackers, and starchy vegetables such as potatoes, beans, and corn are good sources of carbohydrate.
      • Fasting at least 8 to 12 hours before your first blood sample is taken. Do not eat, drink, smoke, or exercise strenuously during the fasting.
      • Must tell your doctor about all prescription and nonprescription medicines you are taking, because it will affect the test results. You may be instructed to stop taking certain medicines before the test.
      How is Done?

      After the preparation, on the day of testing, the following steps will be done:
      • A blood sample will be collected when you arrive. This is your first blood taken to measure your blood sugar (glucose) level before the test. 
      • The next stage is to take a very sweet tasting, glucose drink. It is best to drink the liquid quickly. For the standard glucose tolerance test, you will drink 75 grams or 100 grams. Pregnant women drink 75 grams of glucose.
      • Further blood samples will then be taken either at regular intervals of say 30 or 60 minutes or a single test after 2 hours. The test could take up to 3 hours.Since activity can interfere with test results, you will be asked to sit quietly during the entire test. Do not eat during the test. You may drink only water during this time.
      The Blood Test

      The health professional taking a sample of your blood will:
      • Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
      • Clean the needle site with alcohol.
      • Put the needle into the vein. More than one needle stick may be needed.
      • Attach a tube to the needle to fill it with blood.
      • Remove the band from your arm when enough blood is collected.
      • Apply a gauze pad or cotton ball over the needle site as the needle is removed.
      • Apply pressure to the site and then a bandage.
      What Should the Test Result be?

      For people without diabetes:
      • Fasting value (before the test): under 6 mmol/L
      • At 2 hours: under 7.8 mmol/L
      For people with impaired glucose tolerance (IGT)
      • Fasting value (before the test): under 6.0 to 7.0 mmol/L
      • At 2 hours: under 7.9 to 11.0 mmol/L
      For diabetic levels
      • Fasting value (before the test): under 7.0 mmol/L
      • At 2 hours: over 11.0 mmol/L
      What do these OGT Test Results mean?

      If you fall in the range within the impaired glucose tolerance, you will likely be advised to make lifestyle changes. In some cases, blood glucose lowering medication may be advised.

      If you fall within the diabetic range, it is quite likely that blood glucose medication will be prescribed to help your body keep your blood glucose levels down.

      National Institutes of Health (NIH) stated, that the OGTT it is better able to diagnose high blood glucose after a glucose challenge than the fasting blood glucose test. A doctor may recommend it if he or she suspects diabetes in cases where a patient’s fasting blood glucose level is normal. However, the test is more time-consuming and complicated than the fasting blood glucose test.





      Source & References:
        1. Glucose Tolerance Test - diabetes.co.uk Retrieved last February 26, 2013
        2. Oral Glucose Tolerance Test  - Webmd.com. Retrieved last February 26, 2013 
        3. Glucose Tolerance Test - nlm.nih.gov Retrieved last February 27, 2013 
        4. Image source: http://www.diabetesinfo.org.au/webdata/images/Glucose%20Tolerance%20Test.jpg. Retrieved last February 26, 2013


        How is the Fasting Plasma Glucose test (FPG) done?

        According to American Diabetes Association that the Fasting Plasma Glucose (FPG) test is the preferred method for diagnosing diabetes, because it is easy to do, convenient, and less expensive than other tests. The FPG test measures blood glucose in a person who has fasted for at least 8 hours and is most reliable when given in the morning.

        The test results indicate whether your blood glucose level is normal or whether you have prediabetes or diabetes:
        • Normal: Normal blood sugar levels measure less than 100 mg/dl (milligrams per deciliter) after the fasting glucose test.
        • Prediabetes: Blood glucose levels of 100-125 mg/dl after an overnight or eight-hour fast may indicate prediabetes. People with these results are considered to have impaired fasting glucose (IFG).
        • Diabetes: Diabetes is diagnosed when the blood glucose is 126 mg/dl or above.
        In most cases, your doctor will repeat any abnormal test before confirming the diagnosis.



        Source & References:
          1. How are diabetes and prediabetes diagnosed? - niddk.nih.gov Retrieved last February 26, 2013
          2. What is prediabetes   - Webmd.com. Retrieved last February 26, 2013 
          3. Image source: http://www.elainelau0612.com/stopprediabetes/images/collect_blood_sample.jpg. Retrieved last February 26, 2013

          How is Prediabetes Diagnosed?

          Blood tests are used to diagnosis prediabetes because early in the disease type 2 diabetes may have no symptoms. All diabetes blood tests involve drawing blood at a health care provider’s office or commercial facility and sending the sample to a lab for analysis. Lab analysis of blood is needed to ensure test results are accurate. Glucose measuring devices used in a health care provider’s office, such as finger—stick devices, are not accurate enough for diagnosis but may be used as a quick indicator of high blood glucose.

          In June 2009, an international committee composed of experts from the American Diabetes Association, the European Association for the Study of Diabetes and the International Diabetes Federation recommended that prediabetes testing include the:
          1. Fasting Plasma Glucose (FPG)
          2. Oral Glucose Tolerance Test (OGTT)
          3. Hemoglobin A1C (average blood sugar) Test





          Source & References:
            1. How are diabetes and prediabetes diagnosed? - niddk.nih.gov Retrieved last February 26, 2013
            2. What is prediabetes   - Webmd.com. Retrieved last February 26, 2013 

            Prevention of Prediabetes

            How to Prevent Prediabetes?

            In preventing prediabetes in your body, you must have a healthy lifestyle. It can help you to prevent prediabetes and its progression to type 2 diabetes even if your family history has already runs diabetes.

            Here are some tips to prevent prediabetes:
            • Watch your weight. Being overweight or obese significantly increases your risk for prediabetes, so taking off extra weight is very important. Losing 5% to 10% of your body weight may help you prevent or at least delay type 2 diabetes.2 For example, if you weigh 200 pounds, losing 10 to 20 pounds can reduce your risk. Losing weight can be hard, but you can do it. The easiest way to start is by cutting calories and getting more active. 
            • Be active / Exercise regularly. Working out can help you peel off extra pounds if you need to lose or help you maintain your weight if you're at a healthy weight. When you're active, your body uses glucose. The more active you are, the more glucose your body uses for energy. This keeps the sugar from building up in your blood. Exercise can also improve insulin resistance. Walking is a great way to start.
            • Enjoy healthy food choices. It can be hard to make big changes in the way you eat. It's okay to start small, by limiting the amount foods that are low in fat, sugars, and sodium.  Choose low or zero-calorie beverages over sweetened drinks.  Replace white carbohydrates (i.e. white bread, white rice) with whole grains, brown rice and etc. that are rich in fiber.  
            • Keep blood pressure and cholesterol under control. When you have prediabetes, you are more likely to get heart disease than someone with normal blood sugar levels. If you have high cholesterol, take an active role in controlling it: Aim to exercise at least 30 minutes most days, eat a diet low in saturated fats and don’t smoke. The American Diabetes Association (ADA) recommends maintaining your blood pressure below 130/80 mmHg to prevent the complications that often accompany diabetes.
            • If you smoke, quit. Quitting smoking can help you reduce your risk of getting type 2 diabetes and other health problems. Quitting can also reduce your risk of heart attack and stroke.
            Take a simple steps to prevention

            The National Diabetes Education Program's "Small Steps, Big Rewards" program shows ways you can make small changes to your lifestyle that can have a big impact on preventing prediabetes and type 2 diabetes.

            These changes include:
            • Setting weight-loss goals.
            • Adding exercise to your life.
            • Tracking your progress.
            For more information, see the National Diabetes Education Program Web site at www.ndep.nih.gov.







            Source & References:
            1. Preventing pre-diabetes from becoming diabetes - Foxnews.com Retrieved last February 26, 2013
            2. Prediabetes - Prevention - Mayoclinic.com. Retrieved last February 26, 2013 
            3. Prevention - Webmd.com. Retrieved last February 26, 2013 


            Complications of Prediabetes

            Complications of Prediabetes

            Progression into type 2 diabetes is the most serious consequence of untreated prediabetes.

            Type 2 diabetes complications include:
            • Amputation
            • Blindness
            • Diabetic Ketoacidosis
            • Diabetic Neuropathy
            • Diabetic Retinopathy
            • Eating Disorders
            • Erectile Dysfunctions
            • Foot & Skin Problems
            • Gastroparesis
            • Gum Disease
            • Heart Problems
            • High Blood Pressure
            • Infertility
            • Insulin Shock
            • Kidney Problems
            • Seizures & Coma
            • Peripheral Artery Disease
            • Sexual Problems
            • Urologic Problems
            • Weight Gain
            • Weight Loss





            Source & References:
            1. Medical and Health Disorders Associated With Pre-Diabetes and Insulin Resistance - Pre-diabetes.com Retrieved last February 21, 2013
            2. Prediabetes - Complication - Mayoclinic.com. Retrieved last February 21, 2013 

            Risk Factors of Prediabetes

            What Factors Increase the Risk of Prediabetes?

            As I said in previous articles, people with prediabetes don’t have any signs or symptoms, it is important to be aware of the risk factors and have your blood glucose levels tested by your doctor if you are at risk. 

            Risk Factors Under Your Control

            Many risk factors to consider for prediabetes upon your weight. Here's the following beyond your control:
            • Your Eating Habits: Eating more calories than you need to maintain a healthy weight puts you at risk for pre-diabetes. A diet high in total fat and saturated fat, or too low in complex carbohydrates and fiber may lead to insulin resistance.
            • Inactivity: Lack of physical activity limits the muscles' ability to use insulin, making it more likely that you will become insulin resistant.
            • Observed Abdominal Fat: Having an "apple-shaped" figure with a large waist circumference is the strongest risk factor for prediabetes. Abdominal fat is associated with insulin resistance. Females are at risk when the waist circumference is 35 inches or more. For males, risk increases when the waist is at least 40 inches. Losing weight by changing your eating habits and increasing your physical activity will help you shrink your waist.
            • Your Weight: Obese people with a BMI of 30.0 and above are five times as likely to develop prediabetes when compared with people in the normal weight range. Risk starts to increase at a BMI of 25.
            • Lack of Sleep. Several recent studies have linked a lack of sleep or too much sleep to an increased risk of insulin resistance. Research suggests that regularly sleeping fewer than six hours or more than nine hours a night might up your risk of prediabetes or type 2 diabetes.
            Risk Factors You Cannot Change

            There are a things that we can't control. These are factors which we have no control in developing prediabetes:
            • Your Age: As you get older, your body produces less insulin and becomes less sensitive to the insulin you have. You are at greater risk for prediabetes if you are over 45 years old and overweight, with a BMI of 25 or 23 for Asian Americans. If you are under 45, but are overweight, your risk increases if you have either high blood pressure, a low HDL ("good") cholesterol, high triglycerides, or some combination of the three.
            • Ethnicity / Races: While prediabetes occurs in people of all races, certain ethnic groups have a higher risk than others. Diabetes is more common in African Americans, Latinos, Native Americans, and Asian Americans/Pacific Islanders.
            • Genetics / Family History: If either of your parents have/had type 2 diabetes, then you are more likely to get diabetes too.
            • Gestational Diabetes: If you had diabetes while you were pregnant, but it went away after delivery, you have a 20 percent to 50 percent chance of developing full-blown diabetes in the next 5 to 10 years. Whether or not you had gestational diabetes, you are at greater risk if you had a baby born weighing more than 9 pounds.
            • Polycystic Ovary Syndrome. For women, having polycystic ovary syndrome, is  a common condition characterized by irregular menstrual periods, excess hair growth and obesity will increases the risk of diabetes.




            Source & References:
            1. Prediabetes - Mayo Clinic. Retrieved last February 21, 2013 
            2. Are You at Risk for Pre-diabetes? - CalorieCount.About.com. Retrieved last February 21, 2013