<human>:  What is the purpose of an oral glucose tolerance test?
<bot>: The purpose of an oral glucose tolerance test (OGTT) is to diagnose type 2 diabetes or prediabetes by measuring how well your body is able to process a specific amount of glucose. This test measures the amount of glucose in your blood before and two hours after drinking a special sugary solution. The OGTT is used to confirm a diagnosis of diabetes when there are symptoms or high blood sugar levels and to detect prediabetes before symptoms develop.