An HbA1c level is a reflection of the average glucose level in the blood for the past six to eight weeks, and daily fluctuations in blood glucose do not influence the results, explains eMedicineHealth. A low glucose level is a reading of blood glucose at the time of the test.
Doctors use HbA1c levels as a screening test for diabetes and to monitor the success of management and glucose control in diabetic patients, according to WebMD. The normal range of HbA1c is between 4 and 5.6 percent, and levels between 5.7 and 6.4 percent indicate an increase in the risk of diabetes. The diagnosis of diabetes is made when levels are 6.5 percent or above.
In diabetics, HbA1c levels are measured every three months until the patient reaches the target level of glycemic control, explains WebMD. HbA1c levels above 7 percent indicate an increase in the risk of diabetic complications, including eye disease, kidney disease, nerve damage and stroke, according to MedlinePlus.
The HbA1c test has certain limitations, and some medical conditions have the ability to influence the results, explains eMedicineHealth. The most common causes of falsely elevated HbA1c levels include uremia; chronic, excessive alcohol intake; and hypertriglyceridemia. Some causes of falsely low readings include acute or chronic blood loss, sickle cell disease, and thalassemia.