Where the Thresholds Sit
Reviewed by CDE Mehandi Sharma · Updated
Prediabetes is defined entirely by numbers, so here they are in one place.
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| HbA1c | Below 5.7% | 5.7% to 6.4% | 6.5% or above |
| Fasting glucose | Below 100 mg/dL | 100 to 125 mg/dL | 126 mg/dL or above |
| 2-hour glucose tolerance test | Below 140 mg/dL | 140 to 199 mg/dL | 200 mg/dL or above |
A few things worth noticing when you look at your own report.
The prediabetes bands are narrow. A fasting glucose of 99 mg/dL is called normal and 100 mg/dL is called prediabetes, and there is no meaningful biological difference between them. Where you sit inside a band matters more than which side of a line you fall on.
The tests can disagree. Your fasting glucose can be normal while your two-hour value is not, because they measure different things.
And a single abnormal result usually needs confirming with a repeat before a diagnosis is made.
Keep the numbers themselves, not just the conclusion. A fasting glucose that moved from 118 to 104 over a year is real progress that the word "prediabetes" on both reports completely hides.