More than a third of diabetic patients whose glycated hemoglobin(HbA1c) tests indicate lack of glycemic control are not prescribed adequate treatment changes, according to an Emory University study.

The researchers also found an equal distribution of patients who were tested too often or not enough. Researchers reviewed data of more than 26,000 patients who underwent HbA1c testing over a one-year period, and found that only 4,380 received more than one test. The American Diabetes Association recommends HbA1c testing every six months if patients’ plasma glucose levels are within target range, and every three months otherwise.

Researchers also found that endocrinologists recommended a change in medication or lifestyle in only 63% of cases where serial testing revealed significant increases.HbA1c testing shows the average level of glucose over a three month period. Abnormal results are possible in patients with diseases affecting hemoglobin, such as anemia, as well as patients with kidney or liver disease.

The study was presented at the 2013 American Society for Clinical Pathology Annual Meeting in September. Researchers recommended better communication between labs and clinicians,and noted that physicians are unclear about what constitutes a statistically significant reference change value. Currently, there is no universal algorithm standard to determine whether an increase inHbA1c is statistically significant.