Diagnosis Of Diabetes Using The Oral Glucose Tolerance Test
Diagnosis of diabetes using the oral glucose tolerance test Diagnosis of diabetes using the oral glucose tolerance test BMJ 2009; 339 doi: (Published 28 October 2009) Cite this as: BMJ 2009;339:b4354 1Public Health Sciences Section, Centre for Population Health Sciences, School of Clinical Sciences and Community Health, University of Edinburgh, Edinburgh EH8 9AG May be inaccurate in some ethnic groups, and better tests are needed The prevalence of type 2 diabetes varies greatly by ethnic group within and across countries. The most reliable data on the prevalence of diabetes are based on two hour plasma glucose values after an oral glucose tolerance test,1 which is currently the gold standard epidemiological and clinical diagnostic test for diabetes and impaired glucose tolerance. In Newcastle, England, on the basis of clinical evidence and oral glucose tolerance test results, about 20% of British South Asians had diabetes, compared with only 4% of white Europeans, after age adjustment in a sample of 25-74 year olds.2 Might such observed differences in prevalence, at least in part, be artefacts of the diagnostic method? In 1965, the World Health Organization expert committee drew attention to the lack of suitable epidemiological information about glucose tolerance in various populations of various races and cultures in different countries3 and highlighted the need for research in different populations. The call was repeated in 1980,1 with special reference to the oral glucose tolerance test and the dose of glucose, with 75 g Continue reading >>
Diagnosing And Monitoring Diabetes: What Is Hba1c And How Can It Build Upon Traditional Glucose Testing Methods?
Diabetes mellitus is a common group of metabolic disorders; with a global prevalence of around 8.5%, or approximately 422 million people according to the World Health Organization (WHO) in 2014.1 Characterized by frequent periods of uncontrolled hyperglycemia, diabetes is split into two main types: type 1 and type 2. Type 1 diabetes is characterized by a deficiency of insulin production from the pancreas, which leads to uncontrolled levels of blood glucose. Type 2 diabetes, the most common form, involves either the pancreas not producing enough insulin or the body’s cells becoming resistant to the action of insulin. Diabetes Testing Methods - FBG and OGTT The gold standard diagnostic method for diabetes has previously been the measurement of either fasting blood glucose (FBG) or two-hour plasma glucose via an oral glucose tolerance test (OGTT).2 The diagnostic criteria for a patient to be considered diabetic using FBG or OGTT is: FBG ≥7.0 mmol/l, or Two-hour plasma blood glucose concentration must be ≥11.1 mmol/l two hours following administration of a 75g anhydrous glucose via an OGTT Although both testing methods provide a good level of accuracy, they present their own limitations. Both tests rely on a suitable application of the test within specific time periods and compliance from the patient. Pre-test preparation for testing two-hour plasma blood glucose concentration, for example, includes providing patients with a strict diet for three days prior to testing and overnight fasting. While the FBG test requires a minimum of 8 hours of fasting before the test can be completed. Overall, traditional diagnostic methods can seem daunting and time consuming, which makes patient compliance difficult to achieve. The requirement to fast with traditional glucose testing Continue reading >>
New Diagnostic Tool For Diabetes In Asia | Asian Scientist Magazine | Science, Technology And Medical News Updates From Asia
Malaysia will officially adopt HbA1C as a diabetes diagnostic tool in late 2015 as a supplement to the existing blood glucose test. AsianScientist (Apr. 14, 2015) By Law Yao-Hua From South Asia to the Pacific islands, more than 220 million people are diabetic, making up almost 55 percent of the world total. Half of these diabetes cases are diagnosed, which may later cause life-threatening complications. Earlier and wider detection of diabetes can be achieved if the current diagnosis method, blood glucose analysis, is complemented with hemoglobin A1C (HbA1C), says a review in the Asian Pacific Journal of Tropical Biomedicine. Prior to 2010, measuring blood glucose was the gold standard to diagnose diabetes, using either a fasting plasma glucose test (FPG) or oral glucose tolerance test. Both tests require patients to fast, which is inconvenient for those who have to travel far to a clinic. Also, FPG results can vary more than 12 percent between tests. The results of a FPG depend on how well you fast and what you ate the night before. It is confusing to diagnose someone diabetic in one test but the next test shows normal results, says Usman Malabu, Associate Professor of medicine at James Cook University in Queensland and senior author of the study. Looking for a more reliable alternative to blood glucose analysis, doctors turned to HbA1C. In blood cells, HbA1C forms when glucose binds to hemoglobin. The more glucose there is in the blood and the older the cell, the more HbA1C there is. HbA1C levels can indicate blood glucose levels over the past three months. Since the 1980s, doctors have been using HbA1C to measure and monitor blood glucose levels in diabetic patients. Fasting is not required and results are available within minutes. The test also produces consistent r Continue reading >>
A1c Versus Glucose Testing: A Comparison
Go to: FPG Measurement of glucose in plasma of fasting subjects is widely accepted as a diagnostic criterion for diabetes (1,2). Advantages include inexpensive assays on automated instruments that are available in most laboratories worldwide (Table 1). Nevertheless, FPG is subject to some limitations. One report that analyzed repeated measurements from 685 fasting participants without diagnosed diabetes from the Third National Health and Nutrition Examination Survey (NHANES III) revealed that only 70.4% of people with FPG ≥126 mg/dL on the first test had FPG ≥126 mg/dL when analysis was repeated ∼2 weeks later (6). Numerous factors may contribute to this lack of reproducibility. These are elaborated below. Biological variation Fasting glucose concentrations vary considerably both in a single person from day to day and also between different subjects. Intraindividual variation in a healthy person is reported to be 5.7–8.3%, whereas interindividual variation of up to 12.5% has been observed (6,7). Based on a CV (coefficient of variation) of 5.7%, FPG can range from 112–140 mg/dL in an individual with an FPG of 126 mg/dL. (It is important to realize that these values encompass the 95% confidence interval, and 5% of values will be outside this range.) Preanalytical variation Numerous factors that occur before a sample is measured can influence results of blood tests. Examples include medications, venous stasis, posture, and sample handling. The concentration of glucose in the blood can be altered by food ingestion, prolonged fasting, or exercise (8). It is also important that measurements are performed in subjects in the absence of intercurrent illness, which frequently produces transient hyperglycemia (9). Similarly, acute stress (e.g., not being able to find par Continue reading >>
Detecting Diabetes - Dummies
When prediabetes becomes diabetes, the bodys blood glucose level registers even higher. The following sections discuss the evidence for diabetes and the symptoms you may experience with diabetes. The standard definition of diabetes mellitus is excessive glucose in a blood sample. For years, doctors set this level fairly high. The standard level for normal glucose was lowered in 1997 because too many people were experiencing complications of diabetes even though they did not have the disease by the then-current standard. In November 2003, the standard level was modified again. In 2009, the International Expert Committee on Diagnosis and Classification of Diabetes Mellitus recommended using the hemoglobin A1c as a diagnostic criterion for diabetes, and the American Diabetes Association subsequently accepted the recommendation. After much discussion, many meetings, and the usual deliberations that surround a momentous decision, the American Diabetes Association published the new standard for diagnosis, which includes any one of the following four criteria: Hemoglobin A1c equal to or greater than 6.5 percent. Casual plasma glucose concentration greater than or equal to 200 mg/dl, along with symptoms of diabetes. Casual plasma glucose refers to the glucose level when the patient eats normally prior to the test. Fasting plasma glucose (FPG) of greater than or equal to 126 mg/dl or 7 mmol/L. Fasting means that the patient has consumed no food for eight hours prior to the test. Blood glucose of greater than or equal to 200 mg/dl (11.1 mmol/L) when tested two hours (2-h PG) after ingesting 75 grams of glucose by mouth. This test has long been known as the oral glucose tolerance test. Although this time-consuming, cumbersome test is rarely done, it remains the gold standard for Continue reading >>
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Utility And Limitations Of Glycated Hemoglobin (hba1c) In Patients With Liver Cirrhosis As Compared With Oral Glucose Tolerance Test For Diagnosis Of Diabetes
, Volume 9, Issue1 , pp 243251 | Cite as Utility and Limitations of Glycated Hemoglobin (HbA1c) in Patients with Liver Cirrhosis as Compared with Oral Glucose Tolerance Test for Diagnosis of Diabetes To study the utility of glycated hemoglobin (HbA1c) in the diagnosis of diabetes in patients with cirrhosis as compared to the gold standard oral glucose tolerance test (OGTT) and to see the effect of anemia and severity of cirrhosis on its performance. Individuals (n=100) with an established diagnosis of liver cirrhosis were recruited. The OGTT was performed as described by the World Health Organization (WHO). The severity of cirrhosis was calculated using the ChildTurcottePugh (CTP) score. The severity of anemia was defined according to WHO criteria. The utility of HbA1c was compared against the OGTT results. Test sensitivity and specificity were used to describe the diagnostic accuracy of HbA1c. A total of 100 subjects aged 46.99.1years (meanstandard deviation) participated in the study, of whom 65% were recruited from out patient department of our hospital. The overall sensitivity and specificity of a HbA1c level of 6.5% for the diagnosis of diabetes in patients with cirrhosis was 77.1% (95% CI59.9, 89.6) and 90.8% (95% CI81.0, 96.5), respectively. The positive and negative predictive values were 81.8% (95% CI67.3, 90.8) and 88.1% (95% CI80.0, 93.2), respectively. The area under the curve was 0.85 (95% CI0.750.94). The sensitivity of HbA1c for diagnosing diabetes in outpatients was 87.0% (95% CI 66.4, 97.2) and was better than that for diagnosing diabetes in hospitalized patients (58.3%; 95% CI 27.7, 84.8). The sensitivity of HbA1c for diagnosing diabetes was poor in patients with moderate to severe anemia. The difference in sensitivity and specificity was not statisti Continue reading >>
Diagnosis Of Type 1 Diabetes
By Gary Gilles | Reviewed by Joel Forman, MD The diagnosis of type 1 diabetes can be problematic. Unless there is a known history of diabetes in the family, most people do not recognize the signs and symptoms of type 1 diabetes when they first appear. These symptoms can easily be mistaken for a stomach virus because vomiting is frequently present. As symptoms persist and worsen, most people seek medical attention and only then discover they have type 1 diabetes. Because symptoms begin to appear quickly once the pancreas shuts down its production of insulin ,most people are diagnosed within a short period of time from when the symptoms begin. In some cases, it may take longer. Diagnosing diabetes requires a blood sample to measure glucose levels in the blood. There are three standard tests used for diagnosing type 1 diabetes. The type of test used for any particular person depends on the situation and the doctors preference. These tests are: In an FBG test, a blood sample is obtained after a period of fasting for at least eight hours. This usually means no food or drink (except water) is taken after midnight on the night before the test. A blood sample is usually drawn early the next day before any food is eaten or beverages consumed. If the results of this test revealed a glucose reading of 126 mg/dl or higher it indicates diabetes. To confirm the diagnosis, it is usually necessary to repeat the test a second time on a different day. Fasting glucose levels are normally between 70 to 110 mg/dl in a person without diabetes. The FBG test is the most commonly used test for diagnosing diabetes. In a random blood glucose test, a blood sample is also tested to measure your glucose but there is no consideration given to when you ate your last meal. A glucose level of more than Continue reading >>
In diagnosing diabetes, physicians primarily depend upon the results of specific glucose tests. However, test results are just part of the information that goes into the diagnosis of type 1 or type 2 diabetes. Doctors also take into account your physical exam, presence or absence of symptoms, and medical history. Some people who are significantly ill will have transient problems with elevated blood sugars, which will then return to normal after the illness has resolved. Also, some medications may alter your blood glucose levels (most commonly steroids and certain diuretics, such as water pills). The 2 main tests used to measure the presence of blood sugar problems are the direct measurement of glucose levels in the blood during an overnight fast and measurement of the body's ability to appropriately handle the excess sugar presented after drinking a high glucose drink. Fasting Blood Glucose (Blood Sugar) Level A value above 126 mg/dL on at least 2 occasions typically means a person has diabetes. The Oral Glucose Tolerance Test An oral glucose tolerance test is one that can be performed in a doctor's office or a lab. The person being tested starts the test in a fasting state (having no food or drink except water for at least 10 hours but not greater than 16 hours). An initial blood sugar is drawn and then the person is given a "glucola" bottle with a high amount of sugar in it (75 grams of glucose or 100 grams for pregnant women). The person then has their blood tested again 30 minutes, 1 hour, 2 hours, and 3 hours after drinking the high glucose drink. For the test to give reliable results, you must be in good health (not have any other illnesses, not even a cold). Also, you should be normally active (for example, not lying down or confined to a bed like a patient in a Continue reading >>
The Glucose Tolerance Test, But Not Hba(1c), Remains The Gold Standard In Identifying Unrecognized Diabetes Mellitus And Impaired Glucose Tolerance In Hypertensive Subjects.
Cardiac Research Unit, Cardiology Department, Central Middlesex Hospital, London, United Kingdom. [email protected] The objective of this study was to compare the value of the oral glucose tolerance test (GTT), glycated hemoglobin concentration (HbA(1c)), and fasting plasma glucose (FPG) for identifying unrecognized diabetes mellitus (DM) and impaired glucose tolerance (IGT) in hypertensive subjects. One hundred forty-four consecutive subjects who were not known to have DM and who were attending the Hypertension Clinic underwent 24-hour ambulatory blood pressure (BP) monitoring. A GTT and an HbA(1c) measurement were also carried out. Abnormal results from GTT were found in 94 patients (65%). Results from FPG were not different between those with DM and IGT but were significantly higher than in the euglycemic subjects. The FPG was between 110-125 mg/dL (6.1-6.9 mmol/L) in 31% (n = 20) of patients with IGT and in 53% (n = 16) of those with DM. With use of the previously published criteria to diagnose DM of FPG > or = 103 mg/dL (5.7 mmol/L) and HbA(1c) > or = 5.9%, 33% of our diabetic subjects and 75% of those with IGT would have been misclassified as euglycemic. The previously reported cut-off point for HbA(1c) of >6.1% to diagnose DM was present in 77% of our patients with DM and in 14% (n = 9) of the patients with IGT. Multiple regression analysis showed that an abnormal result from GTT was independent of the level of clinical or ambulatory BP, nocturnal BP dip, cholesterol level, smoking history, race, or class of antihypertensive medication taken. FPG levels or HbA(1c), or their combination, are not accurate enough to identify DM or IGT in patients attending a hospital Hypertension Clinic. A GTT may be required in these patients to reliably identify those wi Continue reading >>
New Diabetes Test Could Be More Accurate
For more than 400 million people with diabetes around the world, blood testing is a routine part of managing their disease. Those tests, however, aren’t always accurate for a variety of reasons. A team of researchers thinks there might be a better way. The researchers say they have devised a new method for estimating blood sugar levels that can reduce errors by more than 50 percent. The researchers published their findings today in the journal Science Translational Medicine. In their study, they combined a mathematical model of hemoglobin glycation in red blood cells with large data sets of patient glucose measurements. It indicated that the age of red blood cells is a major indicator of A1C variation because hemoglobin accumulates more sugar over time. When they controlled the age of cells and tested it on more than 200 people with diabetes, they say the error rate went from 1 in 3 to 1 in 10. One of the researchers, Dr. John Higgins, an associate professor at Harvard Medical School, told Healthline these calculations can be used to correct the test results that people with diabetes now get at their regular checkups. It can also provide an estimate of the A1C result for patients using continuous glucose monitors. Essentially, it has the potential to be the new gold standard in diabetic testing, Higgins said. Read more: Prediabetes: To screen or not to screen? » What’s wrong with current tests The current gold standard for diabetes screening is the glycohemoglobin test (HbA1c). It is a general gauge of diabetes control that specifies an average blood glucose level over a few months. It measures glucose that sticks to hemoglobin inside red blood cells. On a more daily basis, people with diabetes typically check their blood using meters, which measure blood glucose. Continue reading >>
World Diabetes Day 2017 Campaign : Hba1c
Glycated hemoglobin (HbA1c), also called A1C, is a test measuring of the amount of glucose attached to the hemoglobin (Hb) in red blood cells. The higher the glucose levels over the previous 2-3 months, the higher the A1C. In Pantai Premier Pathology, our HbA1c is measured by a High Performance Liquid Chromatography (HPLC) method, which is a NGSP-certified method and Gold Standard in HbA1c testing. This HPLC method is traceable to DCCT reference, providing us the true HbA1c value but not a calculated HbA1c value. The results generated by this HPLC method are free from interference by haemoglobin variants, and not affected by HbC, HbS, HbE or HbD trait. The American Diabetes Association (ADA) recommends using HbA1c to diagnose diabetes using a NGSP-certified method of a cutoff of HbA1c 6.5%. Point of Care (POC) assay methods are not recommended for diagnosis. Using A1c as a Screening Test for Diabetes Measurement of glycated haemoglobin levels revealed that A1c assay showed the least variance in normal subjects compared to plasma glucose levels. OGTT is the gold standard for diagnosing diabetes, it is known to be poorly reproducible and is cumbersome to perform. Using A1c level to diagnose diabetes is convenient since therapeutic decisions are also based on this value, regardless of the findings of the OGTT. Diagnostic Values for Pre-diabetes and Type 2 Diabetes Mellitus Based on A1c: Continue reading >>
New Test For Diagnosis Of Diabetes And Pre-diabetes
The ADA and other organizations will be announcing the guidelines on how to use the A1c test to diagnose diabetes. The test that has been used by most doctors is the fasting blood glucose test. The problem with the fasting blood glucose is that you have to be fasting, but it can still give you a false reading. Now the A1c test which is a 90 day average of your blood sugars will be used, which means fasting will not be required. Leading diabetes organizations in the U.S., as the American Diabetes Association and others will come out with the guidelines within the next couple of months. They will contain information explaining how to use the A1c test as a diagnostic tool for type 2 diabetes. This change is coming at a time when the diagnosis of diabetes has increased over 90% among U.S. adults in the past 10 years. From 4.8 cases per 1,000 population during 1995-97, the number climbed up to 9.1 per 1,000 people in 2005-07 in 33 states. Right now most doctors use the fasting blood sugar result to diagnose diabetes and prediabetes. But we know that you can have a normal fasting blood sugar but still have undiagnosed diabetes. This change will allow us to catch more people with diabetes and they will not have to fast for the test. The glycated hemoglobin test (HbA1c) or the A1c test has been around for more than 30 years. It provides average blood glucose over the previous 90 days. It has become the gold standard test in diabetes care. But, it has not been used as a way to diagnose a person with diabetes because it was not a standardized test. Meaning that a 6% in one lab could be an 8% in another lab. Or that a 6% in one lab is 126mg/dL and a 6% in another lab would be 154mg/dL. It has only been used to find out how a person with diabetes is doing over the last 90 -120 days Continue reading >>
Hemoglobin A1c To Diagnose Diabetes: Why The Controversy Over Adding A New Tool?
Perhaps diabetes is a bit like obscenity: We know it when we see obvious cases, but it is difficult to develop one definition that encompasses the entire spectrum of disease. Hyperglycemia exists on a continuum, and persons destined to develop type 2 diabetes progress along this continuum over time, from having blood glucose concentrations that are physiologic, to those in some intermediate but asymptomatic range, to glucose concentrations that are frankly increased and often associated with acute symptoms and chronic complications of the disease. But at what point does an individual have blood glucose concentrations, or other measures of glycemia, that cross the line from no diabetes to diabetes? Several decades ago, the National Diabetes Data Group (NDDG)2 developed consensus diagnostic criteria for diabetes that were based on population distributions of glucose concentrations (even though for most populations there is not a bimodal distribution for glucose clearly dividing diseased from nondiseased individuals) and based on the relative risk of decompensation to overt or symptomatic diabetes. These criteria, including a fasting plasma glucose (FPG) concentration of 140 mg/dL (7.8 mmol/L) or greater and a 2-h plasma glucose concentration during a 75-g oral glucose tolerance test (OGTT) of 200 mg/dL (11.1 mmol/L) or greater, became the worldwide standard for diagnosing diabetes. Even in 1979, however, the NDDG noted that “there is no clear division between [those with diabetes] and [those without diabetes] in the FPG concentration or their response to an oral glucose load” and acknowledged that the cutpoints chosen were arbitrary (1). In 1997, the Expert Committee on Diagnosis and Classification of Diabetes Mellitus was convened to revisit the criteria for diagnosi Continue reading >>
Hba1c In Type 2 Diabetes Diagnostic Criteria: Addressing The Right Questions To Move The Field Forwards
, Volume 55, Issue6 , pp 15641567 | Cite as HbA1c in type 2 diabetes diagnostic criteria: addressing the right questions to move the field forwards This commentary aims to move the debate regarding the adoption of HbA1c for diagnosis of type 2 diabetes forwards by highlighting the need to avoid addressing irrelevant questions, in particular, comparison of individuals diagnosed with different diagnostic criteria. Instead, we provide a list of important future questions, including whether adoption of HbA1c as the primary diagnostic test improves uptake of diabetes screening, with resultant earlier diagnosis and improvement in outcomes. CardiovascularDiagnosisHbA1cOGTTPrediction Evaluation of Screening and Early Detection Strategies for Type 2 Diabetes and Impaired Glucose Tolerance Much has been written and debated on the benefit of introducing measurement of HbA1c as a diagnostic tool for type 2 diabetes. With an accumulation of supportive data addressing factors such as assay accuracy and linkage to clinical outcomes, many shortcomings have been resolved. Yet, certain issues still cause significant concern amongst some researchers, clinicians and laboratory specialists. To move the debate forwards these issues need to be directly addressed while being mindful that the crucial requirement for a diagnostic tool for diabetes is its ability to identify individuals at risk of future microvascular disease. One of the most common reasons the role of HbA1c as a diagnostic tool is questioned is that it does not identify the same individuals as conventional glucose-based criteria, and a considerable number of studies on this issue continue to be published [ 1 , 2 ]. However, this concern assumes that glucose-based criteria, in particular the OGTT, represent the gold standard for Continue reading >>
Can Hba1c Replace Ogtt For The Diagnosis Of Diabetes Mellitus Among Chinese Patients With Impaired Fasting Glucose?
Can HbA1c replace OGTT for the diagnosis of diabetes mellitus among Chinese patients with impaired fasting glucose? Department of Family Medicine and Primary Care, The University of Hong Kong 3/F, Ap Lei Chau Clinic, No. 161 Main Street, Ap Lei Chau *Correspondence to Esther Y T Yu, Department of Family Medicine and Primary Care, The University of Hong Kong, 3/F, Ap Lei Chau Clinic, No. 161 Main Street, Ap Lei Chau, Hong Kong; E-mail: [email protected] Search for other works by this author on: Department of Family Medicine and Primary Care, The University of Hong Kong 3/F, Ap Lei Chau Clinic, No. 161 Main Street, Ap Lei Chau Department of Family Medicine and Primary Care, The University of Hong Kong 3/F, Ap Lei Chau Clinic, No. 161 Main Street, Ap Lei Chau Division of Family Medicine and Primary Healthcare, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong 2/F, School of Public Health, Prince of Wales Hospital, Shatin, New Territories Department of Family Medicine and Primary Care, The University of Hong Kong 3/F, Ap Lei Chau Clinic, No. 161 Main Street, Ap Lei Chau Family Practice, Volume 32, Issue 6, 1 December 2015, Pages 631638, Esther Y T Yu, Carlos K H Wong, S Y Ho, Samuel Y S Wong, Cindy L K Lam; Can HbA1c replace OGTT for the diagnosis of diabetes mellitus among Chinese patients with impaired fasting glucose?, Family Practice, Volume 32, Issue 6, 1 December 2015, Pages 631638, HbA1c 6.5% has been recommended as a diagnostic criterion for the detection of diabetes mellitus (DM) since 2010 because of its convenience, stability and significant correlation with diabetic complications. Nevertheless, the accuracy of HbA1c compared to glucose-based diagnostic criteria varies among subjects of different ethnicity and risk profile. Continue reading >>
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