How Often Should A Diabetic Take This Test
After a;diabetes diagnosis, this test is often recommended four times per year if glycemic goals are not met. If the glycemic control is stable, then twice per year.;Those with diabetes often must take extra care to keep their;glucose levels;as close to normal as possible.;Chronically high glucose levels lead to problems like damage to the;kidneys, eyes, cardiovascular system, and nerves.;
Small Changes In Temperature Equipment Or Sample Handling
Even when the same blood sample is repeatedly measured in the same lab, the results may vary because of small changes in temperature, equipment, or sample handling. These factors tend to affect glucose measurementsfasting and OGTTmore than the A1C test.
Health care professionals understand these variations and repeat lab tests for confirmation. Diabetes develops over time, so even with variations in test results, health care professionals can tell when overall blood glucose levels are becoming too high.
About Our Hemoglobin A1c Test
The Hemoglobin A1C test evaluates the average amount of glucose in the blood over an 8-12 week time span.
Known as the hemoglobin A1C test or HbA1C test, other names for the test include the glycosylated hemoglobin test, glycohemoglobin test, glycated hemoglobin test, or A1C.
This test is recommended by the American Diabetes Association, the European Association for the Study of Diabetes, and the International Diabetes Federation. It is the primary test used to diagnose prediabetes, type 1 and type 2 diabetes, and to monitor how well you are managing your diabetes.
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Do You Have To Fast For An A1c Blood Test
Unlike the fasting plasma glucose and the OGTT tests, there is no need to fast before having the A1C test. If A1C test results indicate a person has or might have diabetes, a healthcare provider might suggest one of these tests to confirm the results. Another test, the random plasma glucose test, which does not require fasting, can also be used. If the results are borderline or if the results of the different tests do not match, a doctor might suggest repeating the test in several weeks or months.;
Do You Need To Fast For A1c Blood Test
A1c is also used to monitor treatment for individuals diagnosed with diabetes, and even some medications may cause a false positive test, including hemoglobin A1C, its always a good idea to get fasting lipids or other tests done at the same time, You do not need to fast, will draw some blood and send it to a medical laboratory for analysis.
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A1c Blood Test Ok For Diabetes Diagnosis
New Guidelines Call for Using A1C Blood Test to Identify People With Prediabetes
Patients do not need to fast before the test is given, and it is far less likely to identify clinically irrelevant fluctuations in blood sugar because it measures average blood glucose levels over several months.
The new guidelines do not call for replacing traditional screening with the A1C test.
It is believed that around 6 million Americans have diabetes but don’t know it, and another 57 million have prediabetes.
The A1C test may help identify a large number of people in both of these groups, former ADA president for medicine and science John Buse, MD, PhD, tells WebMD.
Buse, who is chief of endocrinology at the University of North Carolina, Chapel Hill, helped draft the new ADA diabetes care guidelines, which were made public today.
“We now know that early diagnosis and treatment can have a huge impact on outcomes by preventing the complications commonly seen when diabetes is not well controlled,” he says. “Our hope is that people with early or prediabetes who might otherwise not be tested would have the A1C test.”
Impact Of Changing The Diagnostic Laboratory Parameter On Epidemiology Of Diabetes
A further critique to the program of moving from FPG to A1C for diabetes diagnosis comes from people who state that epidemiology of the disease is based on FPG and that the scenario would change if A1C were used instead of FPG. A recent report based on the U.S. population showed that the use of A1C rather than FPG would not significantly change diabetes prevalence and that the categorization would not change in as many as 97.7% of subjects. Moreover, this study showed that half of the subjects with FPG 7 mmol/L had an A1C value in the 6.006.49% range, thus deserving strict monitoring and an intervention. In this regard, however, it should be emphasized that any comparison of A1C with FPG is equivocal because a true gold standard is not available. FPG, which in classic studies relating glucose parameters to retinopathy was measured just one time and with less than optimal pre-analytical and analytical procedures, cannot be taken as the gold standard. Therefore, any study examining sensitivity and specificity of A1C for diagnosing diabetes suffers from these limitations and is questionable. At present, the gold standard is probably the combination of FPG, 2-h PG, and A1C assessments with optimal pre-analytical, analytical, and standardized procedures and confirmatory testing for all parameters. This is not feasible on a large-scale basis and cannot be recommended. A1C seems to be a reasonable approach for all reasons discussed above .
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Standardization Of A1c Assay Is Not Inferior To Standardization Of Glucose Assay
One of the main concerns surrounding A1C and raising perplexities on its use for diabetes diagnosis is the poor standardization of the assay. Quite surprisingly, the same concerns and perplexities do not extend to A1C use for diabetes monitoring despite the understanding that only when A1C is aligned to the Diabetes Control and Complications Trial /UK Prospective Diabetes Study standard should the recommended target be pursued . A great effort was made in the U.S. and other countries to make reproducible A1C across laboratories with an effective standardization program. Such a program has been recently completed and is being implemented worldwide to provide more reliable information to physicians who monitor diabetic patients . The standardization is expected to minimize laboratory biases and is a prerequisite to use A1C not only for monitoring but also for diagnosing diabetes.
Although it is generally believed that glucose assay is highly reproducible across laboratories, this is not true. A recent survey conducted in 6,000 U.S. laboratories clearly documented a significant bias in glucose assessment in as many as 41% of them, yielding a misclassification of glucose tolerance in 12% of subjects . Therefore, the argument that A1C cannot be used for diabetes diagnosis because of poor standardization is no longer tenable.
Is Fasting Required For An A1c Test
Blood, or plasma, glucose levels donât remain the same throughout the day. Instead, they fluctuate, especially after a meal. However, this doesnât affect HbA1c testing.
Unlike various other tests for diagnosing or evaluating diabetes, such as the oral glucose tolerance test, fasting is not required with the A1c test. The reason why is simple. This blood glucose test measures your average blood glucose level over the last 90 days, rather than providing a snapshot of your fasting blood glucose level at a particular moment.
For this reason, you do not need to do A1c test fasting, and you can eat and drink as you normally would before the test.
Itâs important to note that the HbA1c test is not a replacement for regular blood glucose monitoring in people with diabetes.
Fasting Is Not Needed For A1c Assessment And No Acute Perturbations Affect A1c
Plasma glucose levels are not stable but rather vary throughout the day, mainly in postprandial periods. Although it is believed that fasting glucose levels are reproducible across days, a number of acute perturbations of glucose homeostasis have been described. Acute stress can increase endogenous glucose production substantially and impair glucose utilization. People who are worried about blood sampling or experience a stressful situation in the hours preceding blood sampling can have an increase in fasting glucose concentration. On the contrary, exercise can decrease glucose levels, and an evening or early-morning session of physical exercise can affect the level of fasting glycemia. Moreover, most individuals do not pay attention to the request or are not asked to consume a diet with at least 200 g carbohydrate in the days before testing glucose. Some individuals do not abstain from food in the 8 h before testing, thus arriving to the laboratory in the postabsorptive rather than fasting condition. In addition, smoking or taking certain medications can adversely affect fasting glucose. The lack of appropriate preparation for glucose testing makes FPG less reliable for diabetes diagnosis, with results sometimes falsely elevated and sometimes apparently normal. On the contrary, A1C is not influenced by acute perturbations or insufficient fasting. Indeed, A1C can be measured anytime, irrespective of fasting or feeding.
Is The A1c Test Used During Pregnancy
Health care professionals may use the A1C test early in pregnancy to see if a woman with risk factors had undiagnosed diabetes before becoming pregnant. Since the A1C test reflects your average blood glucose levels over the past 3 months, testing early in pregnancy may include values reflecting time before you were pregnant. The glucose challenge test or the oral glucose tolerance test are used to check for gestational diabetes, usually between 24 and 28 weeks of pregnancy. If you had gestational diabetes, you should be tested for diabetes no later than 12 weeks after your baby is born. If your blood glucose is still high, you may have type 2 diabetes. Even if your blood glucose is normal, you still have a greater chance of developing type 2 diabetes in the future and should get tested every 3 years.
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What Do My Hba1c Results Mean
In general, the following HbA1c ranges indicate whether you have a normal blood sugar level, prediabetes, or diabetes.
- Your blood sugar level is normal if it is below 5.7%
- You have prediabetes if your level is between 5.7% and 6.4%
- You have diabetes if your level is 6.5% or higher
However, there are exceptions to the general ranges above, so itâs always best to discuss your particular A1c test results with your healthcare provider.
Why Do I Have To Fast
Nutrients in food and drinks go into your bloodstream and can change things measured by the tests, skewing your results.
For instance, if you eat or drink before a fasting blood glucose test, your blood sugar probably will be higher than if you hadn’t had anything. When you’re fasting, doctors get a baseline result so tests can be compared to give a true picture of your sugar levels over time.
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How To Lower Your A1c Level
When you have diabetes, you probably know you should check your blood sugar regularly. Your doctor will also recommend that you take an A1c blood test a few times a year, with a goal of lowering the results to help protect your health. And thereâs a lot you can do to move toward meeting that goal.
Unlike a regular blood sugar test, the A1c test measures the amount of sugar that clings to a protein, called hemoglobin, in your red blood cells. The test shows your average blood sugar levels over the past few months, so you know how well your diabetes is under control.In general, the goal for your A1c is to be lower than 7%. Exactly how much lower will depend on your individual treatment plan. When you take steps to get your A1c in a healthy range, you lower your risk of complications such as nerve damage, eye problems, and heart disease.
Your doctor will let you know the best target for your A1c. How do you get there? Here are a few tactics to try, in addition to taking any medications your doctor prescribes.
Get some new kitchen gear. Youâll want to get a set of measuring cups and a kitchen scale if you donât already have them. These will help you with your portion sizes. Your blood sugar will go up if you eat more food than your body needs. Keeping servings in check is a good way to reduce your A1c level.
When Can I Eat Or Drink Again
As soon as your blood is taken, your fast is over. You might want to bring a snack and a drink with you so you can eat as soon as possible after the test.
American Academy for Clinical Chemistry: “Basic Metabolic Panel,” “Comprehensive Metabolic Panel,” “GGT,” “Glucose Tests,” “Iron Tests,” “Lipid Profile,” “Renal Function Panel,” “Vitamin B12 & Folate.”
British National Health Service: “Can I Eat and Drink Before Having a Blood Test?”
Crystal Moore, MD, PhD, FCAP, anatomical and clinical pathologist, Chesapeake, VA.
National Heart Lung and Blood Institute: “What Are Blood Tests?”
Nemours Foundation: “Blood Test: Comprehensive Metabolic Panel .”
Providence Laboratory Services : “Fasting Instructions.”
How Is The A1c Test Used To Diagnose Type 2 Diabetes And Prediabetes
Health care professionals can use the A1C test alone or in combination with other diabetes tests to diagnose type 2 diabetes and prediabetes. You dont have to fast before having your blood drawn for an A1C test, which means that blood can be drawn for the test at any time of the day.
If you dont have symptoms but the A1C test shows you have diabetes or prediabetes, you should have a repeat test on a different day using the A1C test or one of the other diabetes tests to confirm the diagnosis.2
How Much Does The Test Cost
The full cost of a hemoglobin A1c test depends on many variables, such as what type of hemoglobin A1c test your doctor orders for you, where the test is performed, whether you have medical insurance, and how much of the test cost your insurance provider will cover.
Hemoglobin A1c testing can involve several different charges. These can include fees charged by the laboratory for the technicians labor and the analysis of your sample, as well as the costs of your visits to your doctors office to receive the test or discuss its results.
If your doctor has ordered an hemoglobin A1c test for you, many of these charges will be paid in part or in full by your insurance company. But you may still be responsible for out-of-pocket expenses such as deductibles or copayments. Your doctor or insurance provider can give you more information about the costs that you can expect to pay.
The price of an at-home hemoglobin A1c test device can vary greatly depending on the model and manufacturer, the number of tests that come with the kit, and whether the device is covered by your insurance. You may also need to pay for replacement cartridges or other components if you use the device regularly.
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How Is The A1c Test Used After Diagnosis Of Diabetes
Your health care professional may use the A1C test to set your treatment goals, modify therapy, and monitor your diabetes management.
Experts recommend that people with diabetes have an A1C test at least twice a year.4 Health care professionals may check your A1C more often if you arent meeting your treatment goals.4
Tests For Gestational Diabetes
Gestational diabetes is diagnosed using blood tests. Youll probably be tested between 24 and 28 weeks of pregnancy. If your risk is higher for getting gestational diabetes , your doctor may test you earlier. Blood sugar thats higher than normal early in your pregnancy may indicate you have type 1 or type 2 diabetes rather than gestational diabetes.
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Is It Ok To Drink Water Before A Blood Test
Its fine to drink water before a blood test, unless youre instructed otherwise by your doctor. This is different from some surgical procedures, which may require you to have a totally empty stomach.
Tap or bottled water are both OK, but leave the squeeze of lemon for another time. Seltzer and club soda are off-limits. Carbonated beverages, flavored or otherwise, shouldnt be consumed during a fast, and neither should any type of tea.
What Are Normal A1c Levels
The normal reference range for A1C levels in;healthy adults is 4.8 to 5.7 percent. Most doctors interpret an A1C level of less than 5.7 percent as normal.
If your A1C is between 5.7 percent and 6.4 percent, your diagnosis is prediabetes. This is an important diagnosis, as having prediabetes puts you at risk for developing type 2 diabetes within 10 years.
The criterion for the diagnosis of diabetes is an A1C test greater than or equal to 6.5 percent. If diagnosed with diabetes, the American Diabetes Association recommends an A1C level of less than seven percent as a reasonable therapeutic goal.
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Ask The Doctor: What Blood Tests Require Fasting
Q. Sometimes my doctor tells me it’s okay to eat before a blood test, and sometimes it isn’t. Why is that? A. Actually, fasting affects the results of very few blood tests. For example, measurements of kidney, liver, and thyroid function, as well as blood counts, are not influenced by fasting. However, fasting is required before commonly ordered tests for glucose and triglycerides for accurate results. Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.Continue reading >>
- Postprandial Blood Glucose Is a Stronger Predictor of Cardiovascular Events Than Fasting Blood Glucose in Type 2 Diabetes Mellitus, Particularly in Women: Lessons from the San Luigi Gonzaga Diabetes Study