Objective: The use of glycemic markers in the follow-up of Diabetes Mellitus is important to prevent the development of complications. Glycated hemoglobin (HbA1c) is more stable and exhibits glucose status of 8-12 weeks, while fasting plasma glucose (APG) reflects the current situation, varies from day to day. Therefore, HbA1c is a reliable control mechanism. However, the difference in unit between HbA1c and APG can lead to confusion. To eliminate this condition "Estimated Average Glucose (eAG)" is reported in the same unit with APG, calculated from HbA1c. In our study, we investigated whether it is beneficial to use the eAG.

Material and Methods: In the retrospective study, 690 patients with 75 g Oral Glucose Tolerance Test (OGTT) were chosen from the laboratory information system. Hemoglobin concentrations <12 g/dL (female) and <13 g/dL (male) were grouped as anemia (n = 40) in 234 patients with hemoglobin result. The estimated glucose levels were calculated using the following formula: [(28,7 X HbA1c) - 46,7]. Glucose and HbA1c were measured by hexokinase and "high performance liquid chromatography" methods, respectively.

Results: Hemoglobin values of 36 DM patients diagnosed only with HbA1c were found to be lower than those diagnosed with APG/OGTT (p <0.05). A good correlation was found between eAG and APG levels (r = 0.593, p <0.05). For APG, OGTT and HbA1c the agreement in diagnosing Prediabetes Mellitus and Diabetes Mellitus was only 20.2%.

Conclusion: eAG use will improve glycemic control by eliminating the unit difference between HbA1c and APG. However, since HbA1c and thereby eAG is affected by anemia and conditions that alter the life span of erythrocytes, hemoglobin values can be examined while patients are assessed and the HbA1c and eAG relationship can be calculated again by taking into account the markers that may indicate the erythrocyte life span.