Fasting glucose & OGTT
Also known as:
Fasting plasma glucose, oral glucose tolerance test
Snapshot and stress tests of blood sugar control. The OGTT catches problems a fasting test can miss.
Written and reviewed by Farhan Tahir, MD · Last reviewed
VIDEO LESSON
What they measure
Fasting glucose shows how well the liver's overnight glucose output is controlled. The 2-hour OGTT measures how well your body clears a 75 g glucose drink.
Reading the results
• Fasting 100 to 125 mg/dL: prediabetes; 126 or higher: diabetes
• 2-hour 140 to 199 mg/dL: prediabetes; 200 or higher: diabetes
When the OGTT helps
It is more sensitive in PCOS, after gestational diabetes and when A1c may be unreliable. Avoid it during acute illness.
Key studies and references
Educational content only, written and reviewed by Farhan Tahir, MD. It does not replace individual medical advice. For sudden chest pain, trouble breathing or stroke symptoms, call 911.
AT A GLANCE
Test type
Blood sugar
Also known as
Fasting plasma glucose, oral glucose tolerance test
Reviewed by
Farhan Tahir, MD
Questions about your own care?
Dr. Tahir’s team offers consults through Youthful Medicine.
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