When The A1c Is Unreliable
Although hemoglobin A1c is usually the best test to estimate the average glycemic control in patients with diabetes, it is unreliable in some clinical circumstances. In select patient populations, measuring fructosamine and glycated albumin levels may also be useful. _______________________________________________________________________________________________________________________________________________________ Related Content Diabetes and Cardiovascular Disease: Does Lowering Hemoglobin A1c Help or Harm? Structured Diet Plan Improves A1c in Type 2 Diabetes _____________________________________________________________________________________________________________________________________________________ Q1. What is the A1c and why is it important? A: A1c represents the percent of hemoglobin A with glucose bound to it. While the percent is normally low, in diabetics the higher glucose circulating in the blood causes more hemoglobin binding which results in a higher A1c level. It also can correlate with average glycemic control during the past 2 to 3 months. The American Diabetes Association recommends measuring A1c—≥ 6.5% (48mmol/mol)—as a diagnostic criterion for diabetes and quantifying A1c as the standard laboratory assessment to determine control of type 1 and type 2 diabetes.1 Since the publication of the Diabetes Control and Complications Trial in 1993, we know that A1c levels also directly correlate to the risk of developing diabetic complications such as retinopathy, neuropathy and nephropathy.2 Q2. When is the A1c unreliable? A: For A1c standard test results to be reliable, normal adult hemoglobin A must be present for glucose binding. However, a number of clinically significant disorders alter hemoglobin either structurally or chemically thereby aff Continue reading >>
Inaccurate Glycosylated Hemoglobin A1c Measurements In Human Immunodeficiency Virus—positive Patients With Diabetes Mellitus
With the improved duration of survival for HIV-positive patients, the prevalence of diabetes mellitus among HIV-infected individuals will most likely increase. The incidence of new-onset diabetes is 1%–7% among HIV-infected patients, and several of the antiretroviral medications used to treat HIV infection are associated with significant insulin resistance [1]. In HIV-negative diabetic patients, control of hyperglycemia dramatically reduces microvascular complications associated with diabetes. Measurement of glycosylated hemoglobin (HbA1C) levels is widely used in clinical practice and is a well-validated method for determining average glycemic control over the course of ∼120 days. The American Association of Diabetes recommends checking HbA1C levels ⩾2 times per year for patients with stable glycemic control and more frequently for patients with inadequate control [2]. Fructosamine levels measure glycated serum proteins and provide an additional method for determining average glycemic control [3]. A fructosamine level indicates average glycemic control over a 2–3-week period. Although no specific society-sponsored guidelines exist for the monitoring of diabetes control in HIV-infected patients, some recommend checking HbA1C levels [4]. We report 4 cases of a persistent discordance between patients' blood glucose levels and their HbA1C levels. In each of these cases, HbA1C levels were consistently normal or within an acceptable range for >9 months. However, randomly measured blood glucose levels, home blood glucose monitoring, and fructosamine levels all indicated poor glycemic control. Case reports. Patient 1 was a 42-year-old HIV-positive man who had diabetes mellitus diagnosed after he presented with fatigue, polydipsia, polyuria, and multiple randomly measur Continue reading >>
Hemoglobin A1c (hba1c) (cont.)
When Should Hemoglobin A1c Levels Be Tested? In addition to random fasting blood glucose levels, HbA1c levels are routinely measured (tested) in the monitoring of people with type 1 and type 2 diabetes. HbA1c levels depend on the blood glucose concentration. That is, the higher the glucose concentration in blood, the higher the level of HbA1c. Levels of HbA1c are not influenced by daily fluctuations in the blood glucose concentration but reflect the average glucose levels over the prior six to eight weeks. Therefore, HbA1c is a useful indicator of how well the blood glucose level has been controlled in the recent past (over two to three months) and may be used to monitor the effects of diet, exercise, and drug therapy on blood glucose in people with diabetes. How Can a Person Lower Their HbA1c Levels? Following your type 1 or type 2 diabetes management plan can help lower your HbA1c level. This may consist of dietary modifications, physical activity, medications, a combination of these. A normal or only slightly elevated HbA1c level is an indication that your diabetes is under good control. If your HbA1c level remains high despite following your treatment plan, your doctor may suggest changing your treatment plan. What Are the Limitations to Measuring Hemoglobin A1c? Since HbA1c is not influenced by daily fluctuations in blood glucose concentration, it cannot be used to monitor day-to-day blood glucose concentrations and is inappropriate to be used for adjusting insulin doses; nor can it detect the day-to-day presence or absence of hyperglycemia or hypoglycemia. HbA1c may be increased falsely in certain medical conditions. These conditions include Medical conditions that may falsely decrease HbA1c include A A A Test Overview Glycohemoglobin (A1c) is a blood test that ch Continue reading >>
Drugs Affecting Hba1c Levels
Go to: Diabetes mellitus has assumed epidemic proportions worldwide, causing much morbidity and mortality on account of its various complications. The development of chronic vascular complications of diabetes such as retinopathy, nephropathy and cardiovascular disease is intimately linked to the level of glycemic control attained by the individual with diabetes. Therefore, it is essential to have an index of the long-term glycemic control in diabetes patients, which in turn can be used to guide therapy and predict the likelihood of complications. Glycated hemoglobin (HbA1c) was first described by Rahbar et al. in 1969.[1] Subsequent studies showed that the level of HbA1c correlated well with the glycemic control over a period of 2 to 3 months, leading to the gradual incorporation of the test into clinical practice in the 1980s.[2] With the publication of the Diabetes Control and Complications Trial[3] and the United Kingdom Prospective Diabetes Study,[4] both of which correlated the HbA1c levels to the development of diabetes complications, HbA1c estimation has become established as a cornerstone of diabetes management. Hemoglobin (Hb) is a tetramer formed of two alpha and two beta globin chains. On exposure to high levels of blood glucose, hemoglobin gets non-enzymatically glycated at different sites in the molecule. HbA1c is formed when glucose gets added on to the N-terminal valine residue of the beta chain of Hb.[5] The levels of HbA1c in the blood reflect the glucose levels to which the erythrocyte has been exposed during its lifespan (approximately 117 days in men and 106 days in women). Therefore, the HbA1c is an index of the level of glycemic control over the preceding 2 to 3 months. Of this period, the immediately preceding 30 days contribute 50% to HbA1c.[5] A Continue reading >>
5 Ways To Lower Your A1c
For some, home blood sugar testing can be an important and useful tool for managing your blood sugar on a day-to-day basis. Still, it only provides a snapshot of what’s happening in the moment, not long-term information, says Gregory Dodell, MD, assistant clinical professor of medicine, endocrinology, diabetes, and bone disease at Mount Sinai Health System in New York City. For this reason, your doctor may occasionally administer a blood test that measures your average blood sugar level over the past two to three months. Called the A1C test, or the hemoglobin A1C test, this provides a more accurate picture of how well your type 2 diabetes management plan is working. Taking the A1C Test If your diabetes is well controlled and your blood sugar levels have remained stable, the American Diabetes Association recommends that you have the A1C test two times each year. This simple blood draw can be done in your doctor's office. Some doctors can use a point-of-care A1C test, where a finger stick can be done in the office, with results available in about 10 minutes. The A1C test results provide insight into how your treatment plan is working, and how it might be modified to better control the condition. Your doctor may want to run the test as often as every three months if your A1C is not within your target range. What the A1C Results Mean The A1C test measures the glucose (blood sugar) in your blood by assessing the amount of what’s called glycated hemoglobin. “Hemoglobin is a protein within red blood cells. As glucose enters the bloodstream, it binds to hemoglobin, or glycates. The more glucose that enters the bloodstream, the higher the amount of glycated hemoglobin,” Dr. Dodell says. An A1C level below 5.7 percent is considered normal. An A1C between 5.7 and 6.4 perce Continue reading >>
Glycated Hemoglobin
Glycated hemoglobin (hemoglobin A1c, HbA1c, A1C, or Hb1c; sometimes also referred to as being Hb1c or HGBA1C) is a form of hemoglobin that is measured primarily to identify the three-month average plasma glucose concentration. The test is limited to a three-month average because the lifespan of a red blood cell is four months (120 days). However, since RBCs do not all undergo lysis at the same time, HbA1C is taken as a limited measure of 3 months. It is formed in a non-enzymatic glycation pathway by hemoglobin's exposure to plasma glucose. HbA1c is a measure of the beta-N-1-deoxy fructosyl component of hemoglobin.[1] The origin of the naming derives from Hemoglobin type A being separated on cation exchange chromatography. The first fraction to separate, probably considered to be pure Hemoglobin A, was designated HbA0, the following fractions were designated HbA1a, HbA1b, and HbA1c, respective of their order of elution. There have subsequently been many more sub fractions as separation techniques have improved.[2] Normal levels of glucose produce a normal amount of glycated hemoglobin. As the average amount of plasma glucose increases, the fraction of glycated hemoglobin increases in a predictable way. This serves as a marker for average blood glucose levels over the previous three months before the measurement as this is the lifespan of red blood cells. In diabetes mellitus, higher amounts of glycated hemoglobin, indicating poorer control of blood glucose levels, have been associated with cardiovascular disease, nephropathy, neuropathy, and retinopathy. A trial on a group of patients with Type 1 diabetes found that monitoring by caregivers of HbA1c led to changes in diabetes treatment and improvement of metabolic control compared to monitoring only of blood or urine glu Continue reading >>
When Is Hemoglobin A1c Inaccurate In Assessing Glycemic Control?
Faculty Peer Reviewed Hemoglobin A1C (HbA1c) is an invaluable tool for monitoring long-term glycemic control in diabetic patients. However, many clinicians managing diabetics have encountered the problem of HbA1c values that do not agree with fingerstick glucose logs. Before suspecting an improperly calibrated glucometer or poor patient record keeping, it is useful to consider the situations in which HbA1c may be spuriously elevated or depressed. These issues are best understood after reviewing how HbA1c is defined and measured–topics fraught with considerable confusion. Glycosylation is a non-enzymatic, time-dependent chemical reaction in which glucose binds to the amino groups of proteins.[1] Historically, and long before its precise chemistry was discovered, glycosylated Hb was defined as an area of an elution chromatogram containing hemoglobin glycosylation products. This elution peak was labeled as HbA1, in keeping with the existing nomenclature (HbA, HbA2, HbF, etc. had been identified previously). Later it was recognized that the chromatographic HbA1 region is not homogeneous and consists of several component peaks, designated A1a, A1b and A1c, with HbA1c being the dominant one.[1] The HbA1c fraction also turned out to correlate best with mean serum glucose concentrations, ie, to be a better index of long-term glycemia. Relatively recently HbA1c was redefined chemically: now glycohemoglobin refers to hemoglobin glycosylated at any of its amino groups, while HbA1c is defined as glycohemoglobin with glucose bound specifically to the terminal valine of the beta-globin chain. Consequently, the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has developed a standard reference method for HbA1c in which hemoglobin is cleaved with a specif Continue reading >>
A1c Test Errors
Ads by Google Wise men learn from other men's mistakes; fools insist on learning from their own. ~ Albanian Proverb 9 Undesirable Factors Affecting HbA1C test Any variation in the RBC (or erythrocyte) or hemoglobin may cause hba1c errors. A1C can be increases or decreases by various factors; they are: Decrease or increase in erythrocyte (RBC) makes your A1C lower or increase respectively. Hemoglobin Variants - Hemoglobin S-trait affects about 8% of African Americans. Hemoglobin C trait affects approximately 3% of African Americans. Hemoglobin E trait affects 10% to more than 50% of Southeast Asians in California. These Hb variants are all reported to affect some HbA1c assay methods. Elevated hemoglobin F has an association with thalassemia syndromes, also affects some assay methods. Hypertriglyceridemia interfered with some assay methods and increases result. High bilirubin interferes with some assay methods and increases result. Aspirin interfered with some assay methods and falsely increasing result. Chronic alcohol abuse produces a false high. Splenectomy is a surgical procedure (partial or complete removal of the spleen), this raises A1C. Chronic liver disease has false A1C low. Vitamin C & E ingestion interfere with some assay methods and decrease result. A little doubt saves many a mistake. ~ Albanian Proverb Causes of decrease in erythrocyte that gives lower A1C result: Anemia, Thalassemia or hemolytic anemia, and liver disease, Hemorrhage or bleeding - heavy menstrual periods in women and stomach ulcers, Hemolysis (RBS destruction) - due to transfusion, blood vessel injury, or other causes, Erythropoietin deficiency - secondary to kidney diseases, Uremia (BUN > 85 mg/dl), and Severe nephropathy. Bone marrow conditions - include leukemia, multiple myelomas (plasm Continue reading >>
How Much Does Metformin Lower Hba1c Level?
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Consequences Of Elevated Hba1c In Type 2 Diabetes
Reviewed by Loren Wissner Greene, MD, MA (Bioethics), Clinical Associate Professor of Medicine, NYU School of Medicine, New York, NY Complications of type 2 diabetes are strongly correlated with elevated hemoglobin A1c (HbA1c). Microvascular complications include nephropathy, retinopathy, and neuropathy—while macrovascular complications are primarily manifested by atherosclerosis and resulting cardiovascular morbidity and mortality.1,2 This article reviews the costs and pathogenic mechanisms of these complications in the type 2 diabetes patient. The relationship between HbA1c and microvascular complications of type 2 diabetes has been well characterized. In the United Kingdom Prospective Diabetes Study (UKPDS), a 1% rise in HbA1c was associated with a 37% increase in microvascular disease. Mean follow-up was 10 years.3 The relationship between HbA1c and macrovascular disease appears to be more complex. A large body of observational studies, including the UKPDS, has documented increased incidence of cardiovascular and peripheral vascular disease with increased HbA1c.3,4 However, in the ACCORD trial (Action to Control Cardiovascular Risk in Diabetes), a large randomized study comparing standard glycemic control with intensive glycemic control, no significant improvements in cardiovascular outcomes were achieved with further improvements in HbA1c. Patients with a median HbA1c of 7.5% experienced a rate of cardiovascular events of 7.2%, while those with a lower median HbA1c of 6.4% had a rate of cardiovascular events of 6.9%. This minimal difference was not statistically significant. Not only does HbA1c correlate with clinical outcomes, but studies have also demonstrated its impact on economic costs. In one prospective analysis using a medical claims database, percentage Continue reading >>
Changes In Hba1c Level Over A 12-week Follow-up In Patients With Type 2 Diabetes Following A Medication Change
Abstract Current guidance about the interval needed before retesting HbA1c when monitoring for glycaemic control is based on expert opinion rather than well-powered studies. The aim of our work was to explore how fast HbA1c changes after a change in glucose-lowering medication. This has implications for whether routine HbA1c testing intervals before 12 weeks could inform diabetes medication adjustments. This 12-week cohort study recruited patients from 18 general practices in the United Kingdom with non-insulin treated diabetes who were initiating or changing dose of oral glucose-lowering medication. HbA1c was measured at baseline and 2, 4, 8 and 12 weeks after recruitment. HbA1c levels at earlier time intervals were correlated with 12-week HbA1c. A ROC curve analysis was used to identify the 8-week threshold above which medication adjustment may be clinically appropriate. Results Ninety-three patients were recruited to the study. Seventy-nine patients with no change in medication and full 12-week follow-up had the following baseline characteristics: mean±standard deviation age of 61.3±10.8 years, 34% were female and diabetes duration of 6.0±4.3 years. Mean HbA1c at baseline, 2, 4, 8 and 12 weeks was 8.7±1.5%, (72.0±16.8 mmol/mol) 8.6±1.6% (70.7±17.0 mmol/mol), 8.4±1.5% (68.7±15.9 mmol/mol), 8.2±1.4% (66.3±15.8 mmol/mol) and 8.1±1.4% (64.8±15.7 mmol/mol) respectively. At the end of the study 61% of patients had sub-optimal glycaemic control (HbA1c>7.5% or 59 mmol/mol). The 8-week change correlated significantly with the 12-week change in HbA1c and an HbA1c above 8.2% (66 mmol/mol) at 8 weeks correctly classified all 28 patients who had not achieved glycaemic control by 12 weeks. Conclusions/interpretation This is the first study designed with sufficient pow Continue reading >>
- A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes
- A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes
- Medication Adherence and Improved Outcomes Among Patients With Type 2 Diabetes
Control Of Type 2 Diabetes
Embrace your diabetes Enlarge Haemoglobin, in your blood, joins up with glucose to form the chemical called HbA1c We are learning more about diabetes all the time, and it is becoming clear the harder you work to control your diabetes when it is diagnosed the more benefit you will get in the long term. Complications from diabetes will be prevented or delayed (NEJM 08) (UKPDS 08). Type 2 diabetes is a progressive condition. It is not a 'mild' form of diabetes. The exercise you take and the food you eat need to balance the remaining natural insulin your body makes. This page is designed to give readers an idea how decisions are made concerning their care, but remember every patient is different and advice can vary. Take control....learning how to control type 2 diabetes Your diabetes nurse can teach you the basics, and reading up is helpful. But there are structured diabetes education programs that your doctor must enable you to attend such a course. The programs teach you how to take control of type 2 diabetes, and patients who have attended the program have better diabetic control and fewer problems. Compliance Birmingham meeting 2012: Patients only take half their oral medication. Fixed dose combination tablets would help a little. 10% compliance with multiple drugs. What is happening in type 2 diabetes There are four particular problems. These factors work together to contribute to type 2 diabetes. The factors may be controlled by genes. So your children or brothers and sisters may be affected, and they should take precautions (exercise, healthy diet, not becoming overweight, and not smoking). First, there is a shortage of insulin You may have inherited this condition from your parents. Alternatively, a few people may have had pancreatitis or a bad attack of mumps that Continue reading >>
Drugs Affecting Hba1c Levels.
Abstract Glycated hemoglobin (HbA1c) is an important indicator of glycemic control in diabetes mellitus, based on which important diagnostic and therapeutic decisions are routinely made. However, there are several situations in which the level of HbA1c may not faithfully reflect the glycemic control in a given patient. Important among these is the use of certain non-diabetic medications, which can affect the HbA1c levels in different ways. This review focuses on the non-diabetic medications which can inappropriately raise or lower the HbA1c levels, and the postulated mechanisms for the same. Continue reading >>
Hemoglobin A1c (hba1c) (cont.)
How Is Hemoglobin A1c Measured? The test for hemoglobin A1c depends on the chemical (electrical) charge on the molecule of HbA1c, which differs from the charges on the other components of hemoglobin. The molecule of HbA1c also differs in size from the other components. HbA1c may be separated by charge and size from the other hemoglobin A components in blood by a procedure called high pressure (or performance) liquid chromatography (HPLC). HPLC separates mixtures (for example, blood) into its various components by adding the mixtures to special liquids and passing them under pressure through columns filled with a material that separates the mixture into its different component molecules. HbA1c testing is done on a blood sample. Because HbA1c is not affected by short-term fluctuations in blood glucose concentrations, for example, due to meals, blood can be drawn for HbA1c testing without regard to when food was eaten. Fasting for the blood test is not necessary. What Are Normal Levels of Hemoglobin A1c (Chart)? In healthy people, the HbA1c level is less than 6% of total hemoglobin. A level of 6.5% signals that diabetes is present. Studies have demonstrated that the complications of diabetes can be delayed or prevented if the HbA1c level can be kept below 7%. It is recommended that treatment of diabetes be directed at keeping an individual's HbA1c level as close to normal as possible (<6%) without episodes of hypoglycemia (low blood glucose levels). Chart of Normal and Elevated HbA1c Levels Diagnosis* A1C Level *Any test for diagnosis of diabetes requires confirmation with a second measurement unless there are clear symptoms of diabetes. SOURCE: Centers for Disease Control and Prevention Normal Below 5.7 % Prediabetes 5.7% to 6.4% Diabetes 6.5% or greater What Are High (El Continue reading >>
Drugs Affecting Blood Glucose
Sort Rapid Acting Insulin Lispro (Humalog), aspart (Novolog), and glusine (Apidra). Onset: 15-30 minutes Peak: 1-2 hours Duration: 3-6 hours Used in conjunction with short or intermediate acting insulins for better glycemic control Not to be given IV Insulin determir (Levemir) Slower and longer effect than NPH. Duration at low doses: 12 hours Duration at high doses: 20-24 hours Clear and colorless Administered once or twice per day Not mixed with other insulins Only give subcutaneously Looks clear Sulfonylureas 1. First oral hypoglycemic agents available 2. Promote insulin release from pancreas (you need a functioning pancreas) 3. Derivatives of the sulfonamide antibiotics (cross allergies) 4. May be used alone or combined with other agents 5. First generation (longer duration) second generation (Less side effects) 6. First generation have longer duration of action 7. Hypoglycemia is the number 1 concern 8. Questionable cardiovascular toxicity 9. May cause disulfiram-like reaction when combination with alcohol- drug interaction Thiazolidinediones (Glitazones) Decrease insulin resistance. Acting on the insulin receptors. This type is for type 2 diabetic. Side effects: fluid retention and elevation of lipid levels. Check edema in the sacrum, auscultate the lungs. Remember the end in GLITAZONES Fears of hepatotoxicity appear unfounded DONT GIVE TO A PATIENT WITH SYNDROME X Continue reading >>
