Hemoglobin A1C – StatPearls – NCBI Bookshelf

Introduction

The hemoglobin A1c (glycated hemoglobin, glycosylated hemoglobin, HbA1c, or A1c) test is used to evaluate a person’s level of glucose control. The test shows an average of the blood sugar level over the past 90 days and represents a percentage. The test can also be used to diagnose diabetes.[1]

Hemoglobin is a protein only found in red blood cells. In fact, hemoglobin is what gives blood its bright red coloring. Since red blood cells live about an average of three months, the A1c test will reflect those red blood cells that are present in the bloodstream at the time of the test; this is why the A1c serves as an average of blood sugar control.

The main job of hemoglobin is to carry oxygen from the lungs to all the cells of the body. Hemoglobin becomes glycated or coated with glucose from the bloodstream. The amount of glucose that is present in the blood will attach to the hemoglobin protein, and increased glucose levels will reflect on the surface of the hemoglobin protein, thereby rendering a higher A1c level. [2]

Etiology and Epidemiology

The Diabetes Control and Complications Trial (DCCT)[3] was a landmark trial that provided a wealth of data on A1c and its correlation to blood glucose levels, as well as establishing specific treat to target A1c goals. From the completion of the trial, the National Glycohemoglobin Standardization Program (NGSP) was formed to define a standardized assay that was usable across laboratories.  

The DCCT trial reported that a higher mean A1c level was the dominant predictor of diabetic retinopathy progression. Tighter control shown by levels of HbA1c in the 7% range or lower, were correlated with 35-76% decrease in microvascular complications, like retinopathy, nephropathy and neuropathy, in patients with type 1 diabetes. In addition to the determination of A1c levels predicting progression of microvascular complications, the extension of DCCT into EDIC study showed benefit in the cardiovascular risk and mortality in the longterm for those patients with lower levels of HbA1c. [4][5][6]

Pathophysiology

People with diabetes need to have their A1c checked regularly to determine if their average blood glucose levels are within the target range. The American Diabetes Association (ADA) recommends that the HbA1c is checked twice a year in patients that are stable and well controlled, versus every 3 months in patients with changes in their medications, or not well controlled. [7]

Specimen Requirements and Procedure

The HbA1c test can either be done as a point of care (POC), STAT test, or by sending a sample to a laboratory. The POC test uses a STAT analyzer that evaluates the A1c from a capillary fingerstick. The laboratory test uses a teaspoon of blood drawn from a venous sample into a K2 EDTA (lavender top) tube. The sample gets processed as whole blood.

Diagnostic Tests

The venous sample A1c test may be used as a diagnostic tool in clinical practice when determining diabetes risk or onset. Due to the variability of capillary point of care testing, any A1c done by capillary sample should be confirmed with a venous sample before rendering the diagnosis.

For an HbA1c test to classify as normal, or in the non-diabetic range, the value must be below 5.7 %. Anyone with an HbA1c value of 5.7 % to 6.4 % is considered to be prediabetic, while diabetes can be diagnosed with a HbA1c of 6.5% or higher.

Tests should be sent to a laboratory certified by the NGSP to ensure results are standardized.[8][9]

Testing Procedures

The HbA1c test done by a point of care machine in a doctor’s office may be less accurate than one that is drawn from a venous sample and processed in a laboratory. Typically, the results can vary by different laboratories by as much as 0.5%.

The HbA1c test should be performed using an NGSP-approved method.

Interfering Factors

There are several conditions where the HbA1c test can produce inaccurate results. People diagnosed with sickle cell anemia, thalassemia, anemia, kidney failure, liver disease, or patients receiving blood transfusions can experience altered results due to the longevity of the red blood cell. HbA1c measurement in these patients must be interpreted with caution and should be confirmed with plasma glucose samples to diagnose diabetes.[10]

A falsely low HbA1c value can result from several conditions including high altitude, pregnancy, hemorrhage, blood transfusion, erythropoietin administration, iron supplementation[11], hemolytic anemia, chronic kidney failure, liver cirrhosis, alcoholism, sickle cell anemia[12], and spherocytosis. Vitamin C supplementation can either increase or decrease the HbA1c level depending on the method used for its measurement.[15]

On the other end of the spectrum, a falsely high HbA1c can be due to a lack of available iron in the blood. This condition can result from iron deficiency anemia[13], infection-induced anemia, or tumor-induced anemia. Hemoglobinopathies such as thalassemia and B12 deficiency[11][14] can also cause a falsely high HbA1c. Other causes of falsely high HbA1c levels include hypertriglyceridemia, organ transplantation, and hyperglycation in certain ethnic groups. Medications such as immunosuppressants and protease inhibitors can sometimes lead to a falsely high HbA1c.[10][7][15][16]

Results, Reporting, and Critical Findings

Relationship Between A1c and Glucose Level

The HbA1c percentage equates to an average glucose level in the body that the patient experienced over the past 90 days.[17][18][19]

A1c (%)       Average Blood Glucose (mg/dL)

6                  126

8                  183

10                240

12                298

14                355

Clinical Significance

Hemoglobin A1c serves as an indicator of overall glycemic control and a reflection of the average blood sugar over the past three months.[2]

Quality Control and Lab Safety

Laboratories can use several methods to determine HbA1c. High performance liquid chromatography (HPLC) method is one of the most popular methods because it can eliminate labile components that other methods such as immunoassay or affinity chromatography use. [20]

The point of care (POC) machine is widely used as well to determine HbA1c levels. The variety of POC machines on the market can make it difficult to determine the one best suited for one’s practice. Also, there is a shortage of information comparing the different machines. When using POC testing, one should keep in mind that POC values are often below results reported by a laboratory test, with the mean difference being -0.5%.

Enhancing Healthcare Team Outcomes

All clinicians who look after diabetic patients need to know what HbA1c means. In general, HbA1c provides a measure of the average glucose concentration over three months.

Hemoglobin A1c is often used as an outcome measure to determine if an intervention in a population is successful by showing a decrease in HbA1c by a certain percentage. There is a movement within the medical community to move away from using HbA1c as an exclusive standard of care test to measure patient response to treatment. The Estimated Average Glucose (eAG) and the glucose time in range are the newest proposed methods. [21] These methods use data obtained by continuous glucose monitors (CGMs) that record blood glucose 24 hours a day. They can also give providers a more accurate view of the blood sugar average and fluctuations, but these methods are not available to all patients on a wide-spread basis.

As per ADA guidelines, the levels of HA1c should be measured twice a year in stable patients and at least four times in patients who have glucose fluctuations or those who have had a change in their diabetic treatment. Hemoglobin A1c is one of the preferred diabetes diagnostic tests today. The blood draw can occur at any time, and there are no special handling requirements. However, to ensure that the A1c value is correct, clinicians need to be aware of the causes of false-positive and false-negative results.

Since many patients with diabetes have their condition managed in outpatient clinics, the diabetic nurse should be fully aware of HbA1c values and when to refer the patient to an endocrinologist for further workup and treatment. Pharmacists are also required to fully understand and interpret this test, as they will be involved in glycemic management medication agent selection, dosing, and monitoring.  Both the nurse and/or pharmacist need to inform the treating physician regarding any changes in hemoglobin A1c and verify patient medication compliance. Hemoglobin A1c is a very valuable tool in the fight against diabetes and other glycemic control disorders, but to be effective, it functions best in an interprofessional healthcare team environment. [Level V]

Review Questions

• Access free multiple choice questions on this topic.

• Comment on this article.

References

1.

Gilstrap LG, Chernew ME, Nguyen CA, Alam S, Bai B, McWilliams JM, Landon BE, Landrum MB. Association Between Clinical Practice Group Adherence to Quality Measures and Adverse Outcomes Among Adult Patients With Diabetes. JAMA Netw Open. 2019 Aug 02;2(8):e199139. [PMC free article: PMC6694385] [PubMed: 31411713]

2.

Sherwani SI, Khan HA, Ekhzaimy A, Masood A, Sakharkar MK. Significance of HbA1c Test in Diagnosis and Prognosis of Diabetic Patients. Biomark Insights. 2016;11:95-104. [PMC free article: PMC4933534] [PubMed: 27398023]

3.

Diabetes Control and Complications Trial Research Group. Nathan DM, Genuth S, Lachin J, Cleary P, Crofford O, Davis M, Rand L, Siebert C. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993 Sep 30;329(14):977-86. [PubMed: 8366922]

4.

Nathan DM., DCCT/EDIC Research Group. The diabetes control and complications trial/epidemiology of diabetes interventions and complications study at 30 years: overview. Diabetes Care. 2014;37(1):9-16. [PMC free article: PMC3867999] [PubMed: 24356592]

5.

Nathan DM. Realising the long-term promise of insulin therapy: the DCCT/EDIC study. Diabetologia. 2021 May;64(5):1049-1058. [PubMed: 33550441]

6.

Lachin JM, Orchard TJ, Nathan DM., DCCT/EDIC Research Group. Update on cardiovascular outcomes at 30 years of the diabetes control and complications trial/epidemiology of diabetes interventions and complications study. Diabetes Care. 2014;37(1):39-43. [PMC free article: PMC3868002] [PubMed: 24356596]

7.

American Diabetes Association. 6. Glycemic Targets: Standards of Medical Care in Diabetes-2021. Diabetes Care. 2021 Jan;44(Suppl 1):S73-S84. [PubMed: 33298417]

8.

American Diabetes Association. 6. Glycemic Targets: Standards of Medical Care in Diabetes-2019. Diabetes Care. 2019 Jan;42(Suppl 1):S61-S70. [PubMed: 30559232]

9.

Qaseem A, Wilt TJ, Kansagara D, Horwitch C, Barry MJ, Forciea MA, Clinical Guidelines Committee of the American College of Physicians. Fitterman N, Balzer K, Boyd C, Humphrey LL, Iorio A, Lin J, Maroto M, McLean R, Mustafa R, Tufte J. Hemoglobin A1c Targets for Glycemic Control With Pharmacologic Therapy for Nonpregnant Adults With Type 2 Diabetes Mellitus: A Guidance Statement Update From the American College of Physicians. Ann Intern Med. 2018 Apr 17;168(8):569-576. [PubMed: 29507945]

10.

Heinemann L, Freckmann G. Quality of HbA1c Measurement in the Practice: The German Perspective. J Diabetes Sci Technol. 2015 May;9(3):687-95. [PMC free article: PMC4604529] [PubMed: 25691655]

11.

Pilla R, Palleti SK, Rayana R, Skss SR, Abdul Razzack A, Kalla S. Glycated Haemoglobin (HbA1c) Variations in Nondiabetics With Nutritional Anemia. Cureus. 2020 Nov 13;12(11):e11479. [PMC free article: PMC7735166] [PubMed: 33329975]

12.

Lacy ME, Wellenius GA, Sumner AE, Correa A, Carnethon MR, Liem RI, Wilson JG, Sacks DB, Jacobs DR, Carson AP, Luo X, Gjelsvik A, Reiner AP, Naik RP, Liu S, Musani SK, Eaton CB, Wu WC. Association of Sickle Cell Trait With Hemoglobin A1c in African Americans. JAMA. 2017 Feb 07;317(5):507-515. [PMC free article: PMC5713881] [PubMed: 28170479]

13.

Guo W, Zhou Q, Jia Y, Xu J. Increased Levels of Glycated Hemoglobin A1c and Iron Deficiency Anemia: A Review. Med Sci Monit. 2019 Nov 07;25:8371-8378. [PMC free article: PMC6857442] [PubMed: 31696865]

14.

Gram-Hansen P, Eriksen J, Mourits-Andersen T, Olesen L. Glycosylated haemoglobin (HbA1c) in iron- and vitamin B12 deficiency. J Intern Med. 1990 Feb;227(2):133-6. [PubMed: 2299304]

15.

Radin MS. Pitfalls in hemoglobin A1c measurement: when results may be misleading. J Gen Intern Med. 2014 Feb;29(2):388-94. [PMC free article: PMC3912281] [PubMed: 24002631]

16.

Shepard JG, Airee A, Dake AW, McFarland MS, Vora A. Limitations of A1c Interpretation. South Med J. 2015 Dec;108(12):724-9. [PubMed: 26630892]

17.

van ‘t Riet E, Alssema M, Rijkelijkhuizen JM, Kostense PJ, Nijpels G, Dekker JM. Relationship between A1C and glucose levels in the general Dutch population: the new Hoorn study. Diabetes Care. 2010 Jan;33(1):61-6. [PMC free article: PMC2797987] [PubMed: 19808928]

18.

Sayed A, Alyafei F, De Sanctis V, Soliman A, Elgamal M. Translating the HbA1c assay into estimated average glucose values in children and adolescents with type 1 diabetes mellitus. Acta Biomed. 2018 May 23;89(S5):22-26. [PMC free article: PMC6179094] [PubMed: 30049928]

19.

Lai LC. Global standardisation of HbA1c. Malays J Pathol. 2008 Dec;30(2):67-71. [PubMed: 19291914]

20.

Kawano K. Quality control, quality assessment of laboratory tests, HbA1c. Southeast Asian J Trop Med Public Health. 1999;30 Suppl 3:117-21. [PubMed: 10926271]

21.

Saboo B, Kesavadev J, Shankar A, Krishna MB, Sheth S, Patel V, Krishnan G. Time-in-range as a target in type 2 diabetes: An urgent need. Heliyon. 2021 Jan;7(1):e05967. [PMC free article: PMC7814148] [PubMed: 33506132]

Disclosure: Emily Eyth declares no relevant financial relationships with ineligible companies.

Disclosure: Roopa Naik declares no relevant financial relationships with ineligible companies.

Hemoglobin A1C – StatPearls – NCBI Bookshelf

Introduction

The hemoglobin A1c (glycated hemoglobin, glycosylated hemoglobin, HbA1c, or A1c) test is used to evaluate a person’s level of glucose control. The test shows an average of the blood sugar level over the past 90 days and represents a percentage. The test can also be used to diagnose diabetes.[1]

Hemoglobin is a protein only found in red blood cells. In fact, hemoglobin is what gives blood its bright red coloring. Since red blood cells live about an average of three months, the A1c test will reflect those red blood cells that are present in the bloodstream at the time of the test; this is why the A1c serves as an average of blood sugar control.

The main job of hemoglobin is to carry oxygen from the lungs to all the cells of the body. Hemoglobin becomes glycated or coated with glucose from the bloodstream. The amount of glucose that is present in the blood will attach to the hemoglobin protein, and increased glucose levels will reflect on the surface of the hemoglobin protein, thereby rendering a higher A1c level.[2]

Etiology and Epidemiology

The Diabetes Control and Complications Trial (DCCT)[3] was a landmark trial that provided a wealth of data on A1c and its correlation to blood glucose levels, as well as establishing specific treat to target A1c goals. From the completion of the trial, the National Glycohemoglobin Standardization Program (NGSP) was formed to define a standardized assay that was usable across laboratories.  

The DCCT trial reported that a higher mean A1c level was the dominant predictor of diabetic retinopathy progression. Tighter control shown by levels of HbA1c in the 7% range or lower, were correlated with 35-76% decrease in microvascular complications, like retinopathy, nephropathy and neuropathy, in patients with type 1 diabetes. In addition to the determination of A1c levels predicting progression of microvascular complications, the extension of DCCT into EDIC study showed benefit in the cardiovascular risk and mortality in the longterm for those patients with lower levels of HbA1c. [4][5][6]

Pathophysiology

People with diabetes need to have their A1c checked regularly to determine if their average blood glucose levels are within the target range. The American Diabetes Association (ADA) recommends that the HbA1c is checked twice a year in patients that are stable and well controlled, versus every 3 months in patients with changes in their medications, or not well controlled. [7]

Specimen Requirements and Procedure

The HbA1c test can either be done as a point of care (POC), STAT test, or by sending a sample to a laboratory. The POC test uses a STAT analyzer that evaluates the A1c from a capillary fingerstick. The laboratory test uses a teaspoon of blood drawn from a venous sample into a K2 EDTA (lavender top) tube. The sample gets processed as whole blood.

Diagnostic Tests

The venous sample A1c test may be used as a diagnostic tool in clinical practice when determining diabetes risk or onset. Due to the variability of capillary point of care testing, any A1c done by capillary sample should be confirmed with a venous sample before rendering the diagnosis.

For an HbA1c test to classify as normal, or in the non-diabetic range, the value must be below 5.7 %. Anyone with an HbA1c value of 5.7 % to 6.4 % is considered to be prediabetic, while diabetes can be diagnosed with a HbA1c of 6.5% or higher.

Tests should be sent to a laboratory certified by the NGSP to ensure results are standardized.[8][9]

Testing Procedures

The HbA1c test done by a point of care machine in a doctor’s office may be less accurate than one that is drawn from a venous sample and processed in a laboratory. Typically, the results can vary by different laboratories by as much as 0.5%.

The HbA1c test should be performed using an NGSP-approved method.

Interfering Factors

There are several conditions where the HbA1c test can produce inaccurate results. People diagnosed with sickle cell anemia, thalassemia, anemia, kidney failure, liver disease, or patients receiving blood transfusions can experience altered results due to the longevity of the red blood cell. HbA1c measurement in these patients must be interpreted with caution and should be confirmed with plasma glucose samples to diagnose diabetes.[10]

A falsely low HbA1c value can result from several conditions including high altitude, pregnancy, hemorrhage, blood transfusion, erythropoietin administration, iron supplementation[11], hemolytic anemia, chronic kidney failure, liver cirrhosis, alcoholism, sickle cell anemia[12], and spherocytosis. Vitamin C supplementation can either increase or decrease the HbA1c level depending on the method used for its measurement.[15]

On the other end of the spectrum, a falsely high HbA1c can be due to a lack of available iron in the blood. This condition can result from iron deficiency anemia[13], infection-induced anemia, or tumor-induced anemia. Hemoglobinopathies such as thalassemia and B12 deficiency[11][14] can also cause a falsely high HbA1c. Other causes of falsely high HbA1c levels include hypertriglyceridemia, organ transplantation, and hyperglycation in certain ethnic groups. Medications such as immunosuppressants and protease inhibitors can sometimes lead to a falsely high HbA1c.[10][7][15][16]

Results, Reporting, and Critical Findings

Relationship Between A1c and Glucose Level

The HbA1c percentage equates to an average glucose level in the body that the patient experienced over the past 90 days.[17][18][19]

A1c (%)       Average Blood Glucose (mg/dL)

6                  126

8                  183

10                240

12                298

14                355

Clinical Significance

Hemoglobin A1c serves as an indicator of overall glycemic control and a reflection of the average blood sugar over the past three months.[2]

Quality Control and Lab Safety

Laboratories can use several methods to determine HbA1c. High performance liquid chromatography (HPLC) method is one of the most popular methods because it can eliminate labile components that other methods such as immunoassay or affinity chromatography use. [20]

The point of care (POC) machine is widely used as well to determine HbA1c levels. The variety of POC machines on the market can make it difficult to determine the one best suited for one’s practice. Also, there is a shortage of information comparing the different machines. When using POC testing, one should keep in mind that POC values are often below results reported by a laboratory test, with the mean difference being -0.5%.

Enhancing Healthcare Team Outcomes

All clinicians who look after diabetic patients need to know what HbA1c means. In general, HbA1c provides a measure of the average glucose concentration over three months.

Hemoglobin A1c is often used as an outcome measure to determine if an intervention in a population is successful by showing a decrease in HbA1c by a certain percentage. There is a movement within the medical community to move away from using HbA1c as an exclusive standard of care test to measure patient response to treatment. The Estimated Average Glucose (eAG) and the glucose time in range are the newest proposed methods. [21] These methods use data obtained by continuous glucose monitors (CGMs) that record blood glucose 24 hours a day. They can also give providers a more accurate view of the blood sugar average and fluctuations, but these methods are not available to all patients on a wide-spread basis.

As per ADA guidelines, the levels of HA1c should be measured twice a year in stable patients and at least four times in patients who have glucose fluctuations or those who have had a change in their diabetic treatment. Hemoglobin A1c is one of the preferred diabetes diagnostic tests today. The blood draw can occur at any time, and there are no special handling requirements. However, to ensure that the A1c value is correct, clinicians need to be aware of the causes of false-positive and false-negative results.

Since many patients with diabetes have their condition managed in outpatient clinics, the diabetic nurse should be fully aware of HbA1c values and when to refer the patient to an endocrinologist for further workup and treatment. Pharmacists are also required to fully understand and interpret this test, as they will be involved in glycemic management medication agent selection, dosing, and monitoring.  Both the nurse and/or pharmacist need to inform the treating physician regarding any changes in hemoglobin A1c and verify patient medication compliance. Hemoglobin A1c is a very valuable tool in the fight against diabetes and other glycemic control disorders, but to be effective, it functions best in an interprofessional healthcare team environment. [Level V]

Review Questions

• Access free multiple choice questions on this topic.

• Comment on this article.

References

1.

Gilstrap LG, Chernew ME, Nguyen CA, Alam S, Bai B, McWilliams JM, Landon BE, Landrum MB. Association Between Clinical Practice Group Adherence to Quality Measures and Adverse Outcomes Among Adult Patients With Diabetes. JAMA Netw Open. 2019 Aug 02;2(8):e199139. [PMC free article: PMC6694385] [PubMed: 31411713]

2.

Sherwani SI, Khan HA, Ekhzaimy A, Masood A, Sakharkar MK. Significance of HbA1c Test in Diagnosis and Prognosis of Diabetic Patients. Biomark Insights. 2016;11:95-104. [PMC free article: PMC4933534] [PubMed: 27398023]

3.

Diabetes Control and Complications Trial Research Group. Nathan DM, Genuth S, Lachin J, Cleary P, Crofford O, Davis M, Rand L, Siebert C. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993 Sep 30;329(14):977-86. [PubMed: 8366922]

4.

Nathan DM., DCCT/EDIC Research Group. The diabetes control and complications trial/epidemiology of diabetes interventions and complications study at 30 years: overview. Diabetes Care. 2014;37(1):9-16. [PMC free article: PMC3867999] [PubMed: 24356592]

5.

Nathan DM. Realising the long-term promise of insulin therapy: the DCCT/EDIC study. Diabetologia. 2021 May;64(5):1049-1058. [PubMed: 33550441]

6.

Lachin JM, Orchard TJ, Nathan DM., DCCT/EDIC Research Group. Update on cardiovascular outcomes at 30 years of the diabetes control and complications trial/epidemiology of diabetes interventions and complications study. Diabetes Care. 2014;37(1):39-43. [PMC free article: PMC3868002] [PubMed: 24356596]

7.

American Diabetes Association. 6. Glycemic Targets: Standards of Medical Care in Diabetes-2021. Diabetes Care. 2021 Jan;44(Suppl 1):S73-S84. [PubMed: 33298417]

8.

American Diabetes Association. 6. Glycemic Targets: Standards of Medical Care in Diabetes-2019. Diabetes Care. 2019 Jan;42(Suppl 1):S61-S70. [PubMed: 30559232]

9.

Qaseem A, Wilt TJ, Kansagara D, Horwitch C, Barry MJ, Forciea MA, Clinical Guidelines Committee of the American College of Physicians. Fitterman N, Balzer K, Boyd C, Humphrey LL, Iorio A, Lin J, Maroto M, McLean R, Mustafa R, Tufte J. Hemoglobin A1c Targets for Glycemic Control With Pharmacologic Therapy for Nonpregnant Adults With Type 2 Diabetes Mellitus: A Guidance Statement Update From the American College of Physicians. Ann Intern Med. 2018 Apr 17;168(8):569-576. [PubMed: 29507945]

10.

Heinemann L, Freckmann G. Quality of HbA1c Measurement in the Practice: The German Perspective. J Diabetes Sci Technol. 2015 May;9(3):687-95. [PMC free article: PMC4604529] [PubMed: 25691655]

11.

Pilla R, Palleti SK, Rayana R, Skss SR, Abdul Razzack A, Kalla S. Glycated Haemoglobin (HbA1c) Variations in Nondiabetics With Nutritional Anemia. Cureus. 2020 Nov 13;12(11):e11479. [PMC free article: PMC7735166] [PubMed: 33329975]

12.

Lacy ME, Wellenius GA, Sumner AE, Correa A, Carnethon MR, Liem RI, Wilson JG, Sacks DB, Jacobs DR, Carson AP, Luo X, Gjelsvik A, Reiner AP, Naik RP, Liu S, Musani SK, Eaton CB, Wu WC. Association of Sickle Cell Trait With Hemoglobin A1c in African Americans. JAMA. 2017 Feb 07;317(5):507-515. [PMC free article: PMC5713881] [PubMed: 28170479]

13.

Guo W, Zhou Q, Jia Y, Xu J. Increased Levels of Glycated Hemoglobin A1c and Iron Deficiency Anemia: A Review. Med Sci Monit. 2019 Nov 07;25:8371-8378. [PMC free article: PMC6857442] [PubMed: 31696865]

14.

Gram-Hansen P, Eriksen J, Mourits-Andersen T, Olesen L. Glycosylated haemoglobin (HbA1c) in iron- and vitamin B12 deficiency. J Intern Med. 1990 Feb;227(2):133-6. [PubMed: 2299304]

15.

Radin MS. Pitfalls in hemoglobin A1c measurement: when results may be misleading. J Gen Intern Med. 2014 Feb;29(2):388-94. [PMC free article: PMC3912281] [PubMed: 24002631]

16.

Shepard JG, Airee A, Dake AW, McFarland MS, Vora A. Limitations of A1c Interpretation. South Med J. 2015 Dec;108(12):724-9. [PubMed: 26630892]

17.

van ‘t Riet E, Alssema M, Rijkelijkhuizen JM, Kostense PJ, Nijpels G, Dekker JM. Relationship between A1C and glucose levels in the general Dutch population: the new Hoorn study. Diabetes Care. 2010 Jan;33(1):61-6. [PMC free article: PMC2797987] [PubMed: 19808928]

18.

Sayed A, Alyafei F, De Sanctis V, Soliman A, Elgamal M. Translating the HbA1c assay into estimated average glucose values in children and adolescents with type 1 diabetes mellitus. Acta Biomed. 2018 May 23;89(S5):22-26. [PMC free article: PMC6179094] [PubMed: 30049928]

19.

Lai LC. Global standardisation of HbA1c. Malays J Pathol. 2008 Dec;30(2):67-71. [PubMed: 19291914]

20.

Kawano K. Quality control, quality assessment of laboratory tests, HbA1c. Southeast Asian J Trop Med Public Health. 1999;30 Suppl 3:117-21. [PubMed: 10926271]

21.

Saboo B, Kesavadev J, Shankar A, Krishna MB, Sheth S, Patel V, Krishnan G. Time-in-range as a target in type 2 diabetes: An urgent need. Heliyon. 2021 Jan;7(1):e05967. [PMC free article: PMC7814148] [PubMed: 33506132]

Disclosure: Emily Eyth declares no relevant financial relationships with ineligible companies.

Disclosure: Roopa Naik declares no relevant financial relationships with ineligible companies.

Glycated hemoglobin HbA1c, laboratory equipment, description and characteristics

Hemoglobin glycation is a non-enzymatic reaction between intra-erythrocyte glucose and amino groups of hemoglobin chains. This reaction occurs throughout the lifetime of erythrocytes. Glycated hemoglobin accumulates in erythrocytes during all 120 days of their life. The level of glycated hemoglobin, corresponding to the “combined” value of all glycemic changes in recent weeks, is used as a target in the treatment of diabetes, as well as in the diagnosis of diabetes mellitus.

In accordance with IFCC guidelines, HbA 1 c refers to a stable compound of glucose with the N-terminal amino acid of the β-chain of hemoglobin “A”. And its value is calculated according to the formula

HbA1c = HbA1c / (HbA1c + HbA0)

altered erythrocyte life time, i. e. cause physiological interference.

Results. The result of the assay is an HbA1c quantification expressed in units of IFCC (mmol/mol) and/or NGSP (%) depending on the choice of the operator. As well as a complete hemoglobin profile of the patient, indicating normal or abnormal hemoglobin synthesis.

Research material. whole blood with anticoagulant K2EDTA or K3EDTA.

Sample preparation. hemolysis and sample dilution are fully automated, performed on board.

Catalogs and leaflets

• HbA1c meta-analysis
• HbA1c determination by capillary electrophoresis

Determination of glycated hemoglobin (HbA1c) – All about diabetes

With the help of the HbA1c diabetic barometer, you can detect glucose metabolism disorders in time and take ACTION to prevent the development of diabetes. Also, HbA1c is an effective tool for monitoring the effectiveness for timely correction of treatment and prevention of the development of complications of diabetes. The article describes how HbA1c analysis is performed, its advantages and disadvantages, to whom and how often it is recommended to determine HbA1c.

HOW THE HbA1c INDICATION IS DEVELOPED, IGO PEREVAGI AND NON-DOLILIES

HbA1c is the number of hemoglobin linked to glucose protein, which is found in blood erythrocytes. Normally, HvA1c is 4-5.6%. Glucose binds with hemoglobin for the entire period of erythrocyte life, approximately for three months. In this rank, HbA1c is an indicator of the average blood count for the remaining three months. The highest level of glucose is higher and longer, the highest indicator is HvA1c ^1.2 . Read more about HbA1c indicator: “GLYCING HEMOGLOBIN”.

The analysis of HbA1c will not require specific training and will become a reality. It is necessary to carry out blood tests from a vein in a stationary laboratory. Also, express-analyzers HvA1c are victorious, as they work with blood samples from a finger and for a sprat of whilin give a result. Such portable devices are more suitable for screening for prediabetes. So stinks to give the opportunity to the doctor right in his office to perform analysis and evaluate the compensation of the patient’s diabetes.

HbA1c analysis progress:

• Allows you to estimate the mean blood glucose level for a long period of 3 months, and not just the glucose level at the time of the analysis
• It can be carried out at any hour – for analysis, the camp is not needed (8 year of starvation), which is better for screening
• Less cold due to stress, concomitant illness

HbA1c analysis shortfall:

902 21 Higher variability and lesser availability in the region with blood glucose indicator
• In certain countries and ailments, the indicator of HbA1c can be recorded more low or more high, in fact, the level of glucose in the blood.

Read also: “HbA1c glycation: if the analysis is informative” with rich fate victorious for the manifestation of damage to carbohydrate metabolism, I will become pre-diabetes and circulatory diabetes ^{1, 2, 3}

• in people without diabetes, the HbA1c level is up to 5.6%
• the indicator of 5.7% to 6.4% indicates a possible transmission of diabetes diabetes

HbA1c higher than 6.5% is a serious argument for establishing the diagnosis of “diabetes diabetes”, but in some cases – insufficient ⁴ . DIAGNOSIS cirrhotic diabetes INSTALL LICAR after obstetrics and vaccination of all other criteria, such as: symptoms of diabetes, blood glucose level > 7 mmol/l, blood glucose level with the incidence of follow-up, as well as during the glucose-tolerance test > 11.1 mmol/l ^{3, 4}

TO WHOM AND HOW IT IS FREQUENTLY RECOMMENDED ROBIT HbA1c

^{1, 2, 3, 4}

• Once a day – all people older than 45 years 9020 0
• Once a day – for early detection, I will be IN TENDER to people with high risk development of diabetes; with supra-world vaga, obesity, arterial hypertension and family history of diabetes and heart disease.
• Children on the river – in the presence of PEREDDIABETU (HvA1c 5.6 – 6.4) it is necessary to follow the doctor’s recommendations for eating, physical activity, normalization of the vagi and others for the prevention of the development of diabetic betu
• May be done earlier in case of current pregnancy in order to detect an hourly disturbance in carbohydrate metabolism and prevent the child’s mother from becoming aggravated and exaltation for people with type 2 diabetes with a stable illness.
• Skin 3 months – in case of circulatory diabetes type 1 and insulin therapy in case of type 2 diabetes for monitoring the effectiveness of cerebrovascular therapy and hourly correction therapy

HvA1s – DIABETIC BAROMETER FOR THE PREVENTION OF DIABETES AND YOGO FIXING

HbA1c indicator is also called “Diabetes Barometer”. Similar to a barometer, which indicates the atmospheric pressure and changes the weather, the indicator HvA1c moves the possibility of the development of circulatory diabetes and the improvement of diabetes.