How is the oral glucose tolerance test (OGTT) done?
The OGTT usually requires that you have the fasting glucose test first. Then you take a dose of high-sugar (glucose) solution to challenge your body to clear the glucose from your blood. After two hours, another blood glucose test is done. The final test results indicate whether you have a normal level of blood glucose or have prediabetes or diabetes: • Normal: Normal blood sugar levels measure less than 140 mg/dl after the oral glucose tolerance test. • Prediabetes: Blood glucose levels of 140-199 mg/dl after the OGTT is diagnosed as prediabetes. People with these results are considered to have impaired glucose tolerance (IGT). • Diabetes: Diabetes is diagnosed with blood glucose of 200 mg/dl or above.
