between the glycated haemoglobin levels and the random blood glucose levels. Results correlation exists between levels of HbA1c and random blood sugar. Quarterly HbA1c and corresponding seven-point capillary blood glucose profiles have analyzed the relationship between blood glucose (BG) and HbA1c. . cell life span, or a variant hemoglobin interfering with the HbA1c assay method. The relationship between A1C and eAG is described by the formula X A1C – Translating the hemoglobin A1c assay into estimated average glucose.
The scope of this article is to review the literature to search for enough scientific evidence to support the idea of a close relationship between HbA1c and mean blood glucose MBGand to justify the translation of HbA1c into something that reflects the MBG.
Most studies confirm a close relationship between HbA1c and MBG, although different studies result in different linear equations. Factors affecting this relationship may limit the usefulness and applicability of a unique mathematical equation to all diabetes populations.
The importance of monitoring glycemia has been established by studies proving that there is a direct relationship between mean blood glucose MBG and the development and progression of chronic diabetic complications.
The results of monitoring are used to assess efficacy of therapy and to guide adjust-ments in lifestyle to achieve best possible glucose control.
The most common tests used today for this purpose are blood glucose and glycated hemoglobin GHb. Sincedramatic changes have taken place in both the methods and goals of monitoring.
These changes were driven by accumulation of evidence that complications of diabetes were the result of chronic hyperglycemia and by technological advances in portable glucose meters that permitted since early s patient self-monitoring of blood glucose SMBG to replace urine glucose testing.
During the same period, determination of GHb [most commonly hemoglobin A1c HbA1c ] was found to be a clinically useful measure of glycemic status over the past 3—4 months. Hemoglobin A1c is a term used to describe a series of stable minor hemoglobin components formed slowly and nonenzymatically from hemoglobin and glucose.
This relationship is affected by many factors that can be grouped into two broad categories: Individuals with different HbA1c concentrations, namely 4—6. HbA1c was measured monthly with all analyses performed in a single laboratory to minimize assay variation. It is more difficult to accurately measure average blood glucose than HbA1c.
In order to evaluate average glucose, all study participants underwent continuous glucose monitoring CGM using a MiniMed device for 48 hours every month for 4 months. In addition, all participants measured their blood glucose concentration seven times per day, at least 3 days per week, for the entire duration of the week study.
Is There a Relationship between Mean Blood Glucose and Glycated Hemoglobin?
Thus, over glucose measurements were performed in each subject over the course of the study. Sixty-eight percent of the total participants had completed the study when the presentations were given. Linear regression analysis of this population reveals a good correlation between HbA1c and average blood glucose.
Importantly, subgroup analysis of the population who had completed the study indicates essentially uniform findings. There is no significant difference in the regression equation between males and females, healthy controls or subjects with diabetes, individuals with type 1 or type 2 diabetes, and individuals of different ages.
These results are not unexpected in light of the knowledge that glycation is a nonenzymatic process, which does not appear to be altered substantially by these factors. Nevertheless, the data are reassuring and will enable a single equation to be used for the vast majority of individuals.
Importantly, the correlation fulfilled a priori criteria for acceptance. Therefore, once the study has been completed anticipated by the end ofa regression equation will be derived that will permit conversion of HbA1c results into estimated average glucose eAG values.
Ask the doctor: What's the difference between blood sugar and hemoglobin A1c? - Harvard Health
What are the implications of the study? The outcome is likely to impact both patients and all health care workers, including clinicians, nurses, educators, and laboratory personnel, involved in the management of patients with diabetes.
It is likely that many laboratories will use the final regression equation to calculate an eAG value based on the HbA1c result. This eAG value could be provided in addition to the measured HbA1c concentration.
- Ask the doctor: What's the difference between blood sugar and hemoglobin A1c?
This would be analogous to the current reporting of the estimated glomerular filtration rate, which is derived from the measurement of serum creatinine, along with the measured creatinine value. Many clinicians believe that it will be easier to communicate eAG than HbA1c to patients.
Published studies indicate that many patients do not know whether they had a recent HbA1c measurement or its value 1112 and it is hoped that an explanation of eAG will reduce this lack of knowledge. As with most studies, ADAG suffers from some limitations.