Diabetes Diagnosis & Tests (American Diabetes Association)

Tier 1: Established: peer-reviewed research or government health authority
Publisher: American Diabetes Association · Published: August 24, 2026 · Accessed: August 24, 2026

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Claims this source supports

• Diabetes is diagnosed at a fasting blood glucose of 126 mg/dL or higher.
• Normal fasting plasma glucose is less than 100 mg/dL; prediabetes is 100 to 125 mg/dL.
• Diabetes is diagnosed at an A1C of 6.5% or higher; prediabetes is an A1C of 5.7% to 6.4%; normal is less than 5.7%.
• Each diagnostic test usually needs to be repeated on a second day to diagnose diabetes, unless blood glucose is very high or classic symptoms are present.
• There are no clear symptoms of prediabetes, so you may have it and not know it.