OBJECTIVE: To evaluate whether educational messages regarding oral glucose tolerance test (OGTT) indications in laboratory reports increase the number of OGTTs appropriately requested. RESEARCH DESIGN AND METHODS: The following message was printed on the lab reports of individuals with a fasting plasma glucose (FPG) concentration between 5.5 and 6.9 mmol/l: "A FPG between 5.5 and 6.9 mmol/l is considered abnormal by the American Diabetes Association (impaired fasting glucose). An OGTT is recommended if the patient does not have a diagnosis of diabetes and suffers from conditions associated with an increased risk for having type 2 diabetes (i.e., overweight, high blood pressure, abnormal plasma lipids or family history of diabetes)." The number of educational messages printed was 81,099. RESULTS: The intervention resulted in a significant increase in the number of OGTTs requested, from 78 +/- 19 to 268 +/- 48 tests per month. It also resulted in a greater proportion of case subjects that had an abnormal OGTT result. CONCLUSIONS: Educational messages in laboratory reports aid in the diagnostic workup of hyperglycemia.