Why The A1c Test Is Important
The A1c is a blood test, done in a lab, that shows what your average blood sugar has been for the past 3 months. Other names for this test are glycosylated hemoglobin, glycohemoglobin, hemoglobin A1c, and HbA1c. How the A1c Test Works The glucose that the body doesn't store or use for energy stays in the blood and attaches to red blood cells, which live in the bloodstream for about 4 months. The lab test measures the amount of glucose attached to the red blood cells. The amount is the A1c and is shown as a percentage. Your A1c number can give you and your health care team a good idea of how well you've controlled your blood sugar over the previous 2 to 3 months. When you get your A1c result from a Kaiser Permanente lab, you'll also see another number called the estimated Average Glucose, or eAG. Understanding the eAG Your estimated Average Glucose (eAG) number is calculated from the result of your A1c test. Like the A1c, the eAG shows what your average blood sugars have been over the previous 2 to 3 months. Instead of a percentage, the eAG is in the same units (mg/dl) as your blood glucose meter. The chart shows the relationship between the A1c percentage and the eAG. If A1c % is: Your eAG is: 6 126 6.5 140 7 154 7.5 169 8 183 8.5 197 9 212 9.5 226 10 240 10.5 255 11 269 11.5 283 12 298 What the Numbers Mean The A1c and eAG reflect your average blood sugar over a period of time. These numbers help you and your doctor see how well your treatment plan is working. The higher your A1c and eAG numbers are, the higher your chances for having long-term health problems caused by consistently high blood sugar levels. These problems include heart attacks, strokes, kidney failure, vision problems, and numbness in your legs or feet. The lower your A1c and eAG numbers, the lower you Continue reading >>
Hba1c And Estimated Average Glucose (eag)
Why is relating HbA1c to glucose important? We are frequently asked about the relationship between HbA1c and plasma glucose levels. Many patients with diabetes mellitus now perform self-monitoring of blood glucose (SMBG) in the home setting, and understanding the relationship between HbA1c and glucose can be useful in setting goals for day-to-day testing. HbA1c: A "Weighted" Average Many studies have shown that HbA1c is an index of average glucose (AG) over the preceding weeks-to-months. Erythrocyte (red blood cell) life-span averages about 120 days. The level of HbA1c at any point in time is contributed to by all circulating erythrocytes, from the oldest (120 days old) to the youngest. However, HbA1c is a "weighted" average of blood glucose levels during the preceding 120 days, meaning that glucose levels in the preceding 30 days contribute substantially more to the level of HbA1c than do glucose levels 90-120 days earlier. This explains why the level of HbA1c can increase or decrease relatively quickly with large changes in glucose; it does not take 120 days to detect a clinically meaningful change in HbA1c following a clinically significant change in AG. How does HbA1c relate to average glucose (AG)? In the Diabetes Control and Complications Trial or DCCT (New Engl J Med 1993;329:977-986) study of patients with Type 1 diabetes, quarterly HbA1c determinations were the principal measure of glycemic control; study subjects also performed quarterly 24-hour, 7-point capillary-blood glucose profiles. Blood specimens were obtained by subjects in the home setting, pre-meal, 90 minutes post-meal, and at bed-time. In an analysis of the DCCT glucose profile data (Diabetes Care 25:275-278, 2002), mean HbA1c and AG were calculated for each study subject (n= 1439). Results showed Continue reading >>
All About Your A1c
What has your blood sugar been up to lately? Get an A1C test to find out your average levelsimportant to know if youre at risk for prediabetes or type 2 diabetes, or if youre managing diabetes. The A1C testalso known as the hemoglobin A1C or HbA1c testis a simple blood test that measures your average blood sugar levels over the past 3 months. Its one of the commonly used tests to diagnose prediabetes and diabetes, and is also the main test to help you and your health care team manage your diabetes. Higher A1C levels are linked to diabetes complications, so reaching and maintaining your individual A1C goal is really important if you have diabetes. When sugar enters your bloodstream, it attaches to hemoglobin, a protein in your red blood cells. Everybody has some sugar attached to their hemoglobin, but people with higher blood sugar levels have more. The A1C test measures the percentage of your red blood cells that have sugar-coated hemoglobin. Get a baseline A1C test if youre an adult over age 45or if youre under 45, are overweight, and have one or more risk factors for prediabetes or type 2 diabetes: If your result is normal but youre over 45, have risk factors, or have ever had gestational diabetes, repeat the A1C test every 3 years. If your result shows you have prediabetes, talk to your doctor about taking steps now to improve your health and lower your risk for type 2 diabetes. Repeat the A1C test as often as your doctor recommends, usually every 1 to 2 years. If you dont have symptoms but your result shows you have prediabetes or diabetes, get a second test on a different day to confirm the result. If your test shows you have diabetes, ask your doctor to refer you to diabetes self-management education and support services so you can have the best start in managing Continue reading >>
Welcome To My Hba1c Converter Spreadsheet Page
Here you can download the spreadsheet to calculate your HbA1c percentage by using the average of your blood glucose levels. The creator of the spreadsheet is not a healthcare professional and does not in any way warrants the usability, performance or anything about this spreadsheet. Any damages resulting from the use of this spreadsheet will be limited to the amount of money that you paid me for it. Before downloading the spreadsheet on the right, please read the FAQ. If you still have questions, I can be reached here I would recommend that you put "diabetes" as part of your message subject so that I don't dismiss it as spam. I can not promise that I will answer, but I will try. You will need Microsoft Excel to work with this spreadsheet. Update February 7,2012 Eight years later, my HbA1c remains under control with the help of medication. I uploaded a new version of the spreadsheet since it has been many versions of Excel since I originally created this. The page will remain here for as long as I have my website running so feel free to share. Update November 19, 2003 Well, I finally visited my endocrinologist and got my results from my last week's HbA1c test. The good news is that the test result was 6.3%, which is better than I expected and it is a big improvement over the double digits that showed up when I was diagnosed in July. The other news is that the spreadsheet seems to be doing a half decent job of predicting the HbA1c since the data that I was able to collect before the test (96 Days and 218 different tests) predicted an HbA1c of 6.43%. I uploaded a new version of the spreadsheet, this one has space for 120 days and I changed the conditional formatting a bit. The file is called BVG2.xls and is available to download. If you don't want to open it in the browser Continue reading >>
HbA1c (%) Estimated Average (eAG) (mg/dL) Estimated Average (eAG) (mmol/l) 5 97 5.4 6 126 7.0 7 154 8.6 8 183 10.2 9 212 11.8 10 240 13.4 11 269 14.9 12 298 16.5 You can use the calculators on this page to convert HbA1c and estimated average blood sugars. You can also convert from mg/dL, the measurements used in the USA, and mmol which is used by most of the rest of the world. Convert Blood Sugar from US (mg/dl) to UK (mmol/L) The difference is that mg/dL is a measure of weight while mmol is a measure of volume. US: UK: (click on other box to calculate) Formulas US (mg/dl) is the UK (mmol/L) number multiplied by 18. UK (mmol/L) is the US (mg/dl) number divided by 18. Convert HbA1c to Average Blood Glucose Reading Enter HbA1c (Glycosylated Hemoglobin): % Avg. plasma blood glucose = mg/dl mmol/L Avg. whole blood glucose = mg/dl mmol/L Formulas Avg. Plasma Blood Glucose (mg/dl) = (HbA1c * 35.6) - 77.3 Avg. Plasma Blood Glucose (mmol/L) = (HbA1c * 1.98) - 4.29 Avg. whole blood glucose = Plasma Blood Glucose / 1.12 Continue reading >>
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Hemoglobin, Diabetes, And Statistics!
In previous blog posts, I wrote about quality professional Bill Howell’s diabetes diagnosis and how he managed his disease with Lean Six Sigma. Bill wrote a book, called I Took Control: Effective Actions for a Diabetes Diagnosis, and later when I spoke with him personally, he mentioned the importance of Hemoglobin HbA1c in diagnosing diabetes and how informative this single blood component can be. What is Hemoglobin HbA1c? Hemoglobin HbA1c is a lab test that shows the average amount of sugar in blood cells over a 2-3 month period. The test can also be used to diagnose diabetes and can help diabetics manage their diabetes. If an initial test concludes HbA1c levels are below 7%, then the test is considered normal and the person is likely a non-diabetic. However, if the initial test results show levels above 7%, there is evidence the person is diabetic. I don’t know about you, but when I have blood work and tests performed as part of a visit to the doctors, I don’t take the time to think about the claims behind my tests results coming in as “normal” or “not normal,” or how that decision is made. I’ve always just accepted that if my test results fall within the acceptable range, then I’m probably in good shape. As a newly diagnosed diabetic, Howell’s first HbA1c test revealed his levels at 15.3% – a very high test result that showed he was suffering from severe diabetes. In his role as a quality professional and being a self-proclaimed “numbers junkie,” Howell made sure to find out a little bit more about why the HbA1c guidelines for diagnosing the presence of diabetes were set the way they are and just how abnormal his test results really were. Graphing the “normal” and “not normal” In Minitab Statistical Software, he created histograms (G Continue reading >>
What is HbA1c? HbA1c is formed when haemoglobin (the molecule in red blood cells responsible for carrying oxygen and carbon dioxide) joins up with glucose. Why is HbA1c Important? It can be used to diagnose diabetes and it is a good indicator of your glucose control over the previous 2-4 months. Blood glucose combines with haemoglobin to form HbA1c – so a persistently high blood glucose causes a high HbA1c … Using HbA1c to Diagnose Diabetes HbA1c can be used to diagnose diabetes … HbA1c above 48 mmol/mol (or 6.5%) = diabetes. HbA1c under 42 mmol/mol (or 6.0%) = not diabetic. HbA1c between 42-48 mmol/mol (or 6.0-6.5%) is ‘pre-diabetes’ or ‘at high risk of diabetes’. Using HbA1c to Monitor Diabetes As shown above, HbA1c is an indication of your average blood sugar over the previous 2-4months. *It is very important that your own target should be set by your GP or diabetic care team. *People without diabetes should have an HbA1c of around 20-41 mmol/mol. *Diabetics will have varying targets depending on their likelihood to experience low blood glucose. *HbA1c used to be recorded as a percentage (e.g. 6.0%) – it is now recorded as a number (e.g. 42 mmol/mol). Here is a conversion table … 6.0% = 42 mmol/mol 6.5% = 48 mmol/mol 7.0% = 53 mmol/mol 7.5% = 58 mmol/mol 8.0% = 64 mmol/mol 9.0% = 75 mmol/mol Who Should Be Tested? Undiagnosed? If you are not diabetic but are at high risk on our Self Assessment Tool or if you have symptoms of tiredness, thirst and passing urine frequently you should see your GP who may well decide to test your HbA1c. Type 2 Diabetic? You should be tested every 3 months if you are trying to improve your blood glucose control, or every 6 months if your control is stable. Type 1 Diabetic? HbA1c testing is not recommended for children or Continue reading >>
Hba1c Increases With Age
HbA1c levels in the elderly rise but not in precise relationship to glucose tolerance…. In this cross-sectional analysis of adults with known diabetes, impaired glucose tolerance and HbA1c levels increased with age, even after adjusting for covariates including race, BMI, waist circumference, sagittal abdominal diameter, triglyceride/HDL ratio, and fasting and 2-hour plasma glucose levels assessed by an oral glucose tolerance test. The specificity of HbA1c-based prediabetes diagnosis decreased substantially as age increased. "For the same level of blood glucose, HbA1c is higher in the elderly, suggesting a decreased specificity for the diagnosis of diabetes with increasing age. Given that glucose levels may be normal, basing a diagnosis on HbA1c will result in more risk for hypoglycemia with treatment; on the other hand, one wonders whether the higher HbA1c reflects decreased clearance that may also apply to tissues damaged by glucose, rendering them more susceptible to damage in the presence of ‘normal’ glucose levels," said the researchers. Examining the measures of sensitivity, specificity, and negative and positive predictive value based on HbA1c criteria using the OGTT as gold standard, the researchers found a remarkable decrement in performance, predominantly sensitivity, with age. This is an issue superimposed on the well-recognized problem that the sensitivity of HbA1c for diagnosis of diabetes compared with OGTT is quite limited, clustering in most populations around 50%. Researchers concluded that in two large datasets, using different methods to measure HbA1c, the association of age with higher HbA1c levels was consistent and similar; was both statistically and clinically significant; was unexplained by features of aging; and reduced diagnostic specific Continue reading >>
The Formulas Equating Hba1c To Average Glucose Level Don't Work With Near Normal Blood Sugars?
NOTE: Important New Information Added to this post in OCT 2007. Please scroll to bottom to read! I got my new A1c result yesterday, the first in six months. It was 5.5%. During this period, my blood sugars have been significantly better than they had been for years. My fasting blood sugars have dropped about 20 mg/dl and my post-meal values have dropped by about 30 mg/dl. These changes have been measured many times using reference meals with known blood sugar outcomes. In the past, my A1cs were almost always 5.7%. The drop in A1c doesn't seem to capture the significant lowering of my blood sugars over this period. The usual formula to estimate the relationship between A1c and mean plasma glucose was derived from the DCCT study. That formula is: Mean Blood Glucose = (A1c * 35.6) - 77.3 Applying this formula, an A1c of 5.5% is supposed to correspond to a mean plasma glucose of 118.5 mg/dl and an A1c of 5.7% is supposed to correspond to a mean plasma glucose of 125.6 mg/dl. Neither of these values correspond to anything I have ever seen in my testing, and I test a lot and at many different times of day. My 30 day meter average, based on 150 measurements, has ranged between 98 and 103 during this period. There is another, less cited formula that works better, at least for me. It is called "The Nathan Formula" it is: Mean Plasma Glucose = (A1c * 33.3) -86 This formula yields a mean plasma glucose value of 97 mg/dl, which comes much closer to what my meter's 30 day average has looked like throughout this period. Here's a calculator that will give you the Nathan Formula A1c/Mean Plasma Glucose equivalents: A1c Calculator However, I think the most important point is this: despite doctors' reliance on A1c it is not a particularly accurate measurement of what your blood sugars ha Continue reading >>
Your A1c Levels – What Goal To Shoot For?
Measuring Your A1C An A1C test gives you and your provider insight into all of your blood glucose ups and downs over the past two or three months. It’s like the 24/7 video of your blood sugar levels. Observing your A1C results and your blood glucose (also known as blood sugar) results together over time are two of the key tools you and your health care provider can use to monitor your progress and revise your therapy as needed over the years. Recent research is changing the way health professionals look at A1C levels. Instead of setting tight controls across the board, a healthy A1C level is now a moving target that depends on the patient. In the past, an A1C of 7 percent was considered a healthy goal for everyone. Yehuda Handelsman, M.D., medical director of the Metabolic Institute of America in Tarzana, California, says experts now recommend taking a patient-centered approach to managing A1C levels, which means evaluating goals based on individual diabetes management needs and personal and lifestyle preferences. Current ADA Goals The 2015 American Diabetes Association (ADA) Standards of Medical Care in Diabetes advise the following A1C levels: • 6.5 percent or less: This is a more stringent goal. Health care providers might suggest this for people who can achieve this goal without experiencing a lot of hypoglycemia episodes or other negative effects of having lower blood glucose levels. This may be people who have not had diabetes for many years (short duration); people with type 2 diabetes using lifestyle changes and/or a glucose-lowering medication that doesn’t cause hypoglycemia; younger adults with many years to live healthfully; and people with no significant heart and blood vessel disease. • 7 percent: This is a reasonable A1C goal for many adults with d Continue reading >>
HbA1c is a blood test that is used to help diagnose and monitor people with diabetes. It is also sometimes called a haemoglobin A1c, glycated haemoglobin or glycosylated haemoglobin. What is being tested? HbA1c refers to glucose and haemoglobin joined together (’glycated’). Haemoglobin is the protein in red blood cells that carries oxygen throughout your body. The amount of HbA1c formed is directly related to the amount of glucose in your blood. Red blood cells live for up to 4 months, so HbA1c gives an indication of how much sugar you’ve had in your blood over the past few months. It’s different to the blood glucose test, which measures how much sugar you have in your blood at that moment. Why would I need this test? The test for HbA1c indicates how well your diabetes has been controlled over the last few months. It can also be used to diagnose diabetes. People with diabetes are advised to have this test every 3-6 months, or more frequently if it is not under control. This is important. The higher the HbA1c, the greater the risk of developing complications such as problems with your eyes and kidneys. How to prepare for this test No preparation is needed for this test. Understanding your results If you have not previously been diagnosed as having diabetes, an HbA1c of 6.5% or more can indicate that you do have diabetes. If your level is lower than this, you might need other tests to check whether you have diabetes or not. If you do have diabetes, your doctor will usually aim for an HbA1c of 6.5-7%. If the HbA1c is higher than the target range, your doctor may consider changing your treatment or closer monitoring. There are some medical conditions, such as anaemia, that change red blood cells and affect your HbA1c result. You should discuss the results with your Continue reading >>
How To Calculate Your A1c
The Hemoglobin A1c (HbA1c or simply A1c for short) test is a blood test used to measure the average blood glucose concentration in your body in the past 1-3 months. For diabetics, this is the standard way of determining how well the diabetes is controlled. An A1c of less than 7% is considered good. Getting the test every 3 months (usually during a doctor visit) is usually enough. But sometimes you may want to just estimate your A1c level based on the data from your regular self-tests. The formula below could help in this case. Accuracy, of course, could vary depending on how often and when you check your blood sugar. I found it pretty accurate last time I used it. My calculation was off only by 0.1%. This is the same formula GlucoseTracker uses in the app's dashboard. Glucose in mg/dL: A1c = (46.7 + average_blood_glucose) / 28.7 Glucose in mmol/L: A1c = (2.59 + average_blood_glucose) / 1.59 So, for example, if your average blood glucose level in the past 3 months is 130 mg/dL (7.2 mmol/L) , your estimated A1c is 6.15%. There are also cheaper devices you can buy that will allow you to do the actual A1c tests yourself, like this one. If you need to do these tests more often, say every month, then it could save you money in the long run as lab tests could get expensive. It may not be as accurate as the lab tests, but my guess is it's probably good enough. Continue reading >>
HbA1c Calculator With this tool you can easily convert HbA1c values from % (NGSP) to mmol/mol (IFCC) and vice versa. In addition, average blood glucose levels can be determined in mg/dL and mmol/L. By insertion of any value all other fields will update automatically. Background The International Consensus Statement of US and European Diabetes Associations recommend consistent standardization of the HbA1c determination to the IFCC1 reference measurement procedure, using the new unit mmol/mol. Since these new values in mmol/mol differ from values determined by the standardization according to NGSP2, it is recommended that HbA1c results should be reported in both units, mmol/mol (SI unit) and derived NGSP units (in %). By means of the calculator above, IFCC values in mmol/mol can be converted into NGSP values in % and vice versa. 1International Federation of Clinical Chemistry 2National Glycohemoglobin Standardization Programme Continue reading >>
All About The Hemoglobin A1c Test
People with diabetes used to depend only on urine tests or daily finger sticks to measure their blood sugars. These tests are accurate, but only in the moment. As an overall measurement of blood sugar control, they’re very limited. This is because blood sugar can vary wildly depending on the time of day, activity levels, and even hormone changes. Some people may have high blood sugars at 3 a.m. and be totally unaware of it. Once A1C tests became available in the 1980s, they became an important tool in controlling diabetes. A1C tests measure average blood glucose over the past two to three months. So even if you have a high fasting blood sugar, your overall blood sugars may be normal, or vice versa. A normal fasting blood sugar may not eliminate the possibility of type 2 diabetes. This is why A1C tests are now being used for diagnosis and screening of prediabetes. Because it doesn’t require fasting, the test can be given as part of an overall blood screening. The A1C test is also known as the hemoglobin A1C test or HbA1C test. Other alternate names include the glycosylated hemoglobin test, glycohemoglobin test, and glycated hemoglobin test. A1C measures the amount of hemoglobin in the blood that has glucose attached to it. Hemoglobin is a protein found inside red blood cells that carries oxygen to the body. Hemoglobin cells are constantly dying and regenerating, but they have a lifespan of approximately three months. Glucose attaches, or glycates, to hemoglobin, so the record of how much glucose is attached to your hemoglobin also lasts for about three months. If there’s too much glucose attached to the hemoglobin cells, you’ll have a high A1C. If the amount of glucose is normal, your A1C will be normal. The test is effective because of the lifespan of the hemogl Continue reading >>
Hba1c And Monitoring Glycaemia
This article forms part of our ‘Tests and results’ series for 2012, which aims to provide information about common tests that general practitioners order regularly. It considers areas such as indications, what to tell the patient, what the test can and cannot tell you, and interpretation of results. Proteins in the body chemically react with glucose and become glycosylated. HbA1c is glycosylated haemoglobin and reflects the average blood glucose over the lifespan of the red blood cells containing it. HbA1c is regarded as the gold standard for assessing glycaemic control. HbA1c is also known as A1c, glycohaemoglobin and glycated haemoglobin. When should HbA1c be ordered? HbA1c reflects average glycaemia over the preceding 6–8 weeks. The test is subsidised by Medicare up to four times in a 12 month period.1 In some patients, HbA1c may be measured more frequently than 3 monthly to closely monitor glycaemic control (eg. in pregnancy when up to six tests in a 12 month period can be subsidised).1 The Service Incentive Program for diabetes care requires at least one HbA1c measurement per year. It is suggested that HbA1c is done every 6 months if meeting target, or every 3 months if targets are not being met or if therapy has changed.2 Self blood glucose monitoring (BGM) and HbA1c complement each other: BGM informs the patient about blood glucose at any particular time (eg. when the patient feels hypoglycaemic) and informs the patient and doctor about the glycaemic pattern over the 24 hour cycle and guides the timing and level of lifestyle intervention and hypoglycaemic therapy. What do I tell my patient? HbA1c is tested using venous blood, taken at any time of day and without any preparation such as fasting. In the paediatric setting, a finger-prick capillary sample can Continue reading >>
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