Oral Glucose Tolerance Test(OGTT)
Definition
A diagnostic test in which the patient drinks a 75-gram glucose solution after fasting, with blood glucose measured at 0, 1, and 2 hours to evaluate glucose metabolism. A 2-hour value below 140 mg/dL is normal, 140 to 199 mg/dL indicates impaired glucose tolerance (prediabetes), and 200 mg/dL or above confirms diabetes. CGM data during an OGTT provides a complete glucose curve rather than just 2 or 3 data points, revealing the peak glucose level, time to peak, and recovery pattern that point-in-time blood draws miss.
Why “Oral Glucose Tolerance Test” Matters for Glucose Monitoring
Understanding oral glucose tolerance test is essential for anyone using or evaluating a continuous glucose monitor. This concept directly affects how CGM devices are designed, how glucose data is interpreted, and how clinical decisions about blood sugar management are made.
This term applies broadly across all continuous glucose monitors and is foundational knowledge for interpreting CGM data, whether you are managing diabetes or using a sensor for metabolic wellness.
Related Terms
Hemoglobin A1C is a blood test that measures the percentage of hemoglobin proteins coated with sugar, reflecting average blood glucose levels over the previous 2 to 3 months.
A metabolic condition in which the body's cells respond poorly to the hormone insulin, forcing the pancreas to produce progressively larger amounts to maintain normal blood glucose levels.
Blood glucose levels measured after eating, typically peaking 60 to 90 minutes after a meal and returning to baseline within 2 to 3 hours in healthy individuals.