IFG: What “Impaired Fasting Glucose” Actually Means
IFG stands for Impaired Fasting Glucose, a form of prediabetes where your fasting blood sugar measures 100 to 125 mg/dL (5.6 to 6.9 mmol/L). It is above the normal range but below the diabetes threshold, and it signals a rising risk of type 2 diabetes.
If a lab report or a doctor mentioned IFG, it is one of the most common early signals that your blood sugar control is starting to slip, and one of the most reversible. Here is exactly what the term means, the numbers behind it, and what to do next.
What does IFG stand for?
IFG stands for Impaired Fasting Glucose. In medical notes and lab results it is the shorthand for a fasting blood sugar that is higher than normal but not high enough to be called diabetes. It is one of the two ways prediabetes is defined.
What is impaired fasting glucose?
Impaired fasting glucose means that after not eating for at least 8 hours, your blood glucose is elevated but still below the diabetes range. It is an early, usually reversible stage where the body is beginning to lose tight control of blood sugar. Because it rarely causes symptoms, most people only find out from a routine blood test.
What blood sugar level counts as IFG?
The thresholds come from a simple fasting blood glucose test:
| Category | Fasting glucose (mg/dL) | Fasting glucose (mmol/L) |
|---|---|---|
| Normal | Below 100 | Below 5.6 |
| Impaired fasting glucose (IFG) | 100 – 125 | 5.6 – 6.9 |
| Diabetes | 126 or higher | 7.0 or higher |
These are the American Diabetes Association ranges. The World Health Organization uses a slightly narrower IFG band of 110–125 mg/dL. A single reading over 100 is not a diagnosis on its own; it should be confirmed with a repeat test.
What is the difference between IFG and IGT?
Prediabetes is the umbrella term, and IFG is one of two routes to it:
- IFG (Impaired Fasting Glucose): based on your fasting number.
- IGT (Impaired Glucose Tolerance): based on how high your glucose climbs two hours after a glucose drink (an oral glucose tolerance test).
You can have one, the other, or both. Some people with a normal fasting number still spike sharply after meals, a pattern a fasting test alone would miss.
Is impaired fasting glucose serious?
IFG is a warning light, not a life sentence. Left unaddressed, it raises the risk of progressing to type 2 diabetes, and it is independently linked to higher cardiovascular risk. The good news: this is the stage where change works best. Many people return their fasting glucose to normal through modest weight loss, moving after meals, and adjusting what and when they eat.
See the full picture, not just one number
A fasting test is a single snapshot. It can’t show the shape of your glucose across the day: the post-meal spikes and overnight drift that often appear before your fasting number ever crosses 100. A continuous glucose monitor makes that visible, and Endobits turns those curves into a plain-language read on where your metabolic health actually stands.
Check my glucoseSources
- American Diabetes Association. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes—2026. Diabetes Care 2026;49(Suppl. 1):S27–S49. 10.2337/dc26-S002
- World Health Organization. Definition and diagnosis of diabetes mellitus and intermediate hyperglycaemia. Geneva: WHO. who.int
- Endotext (NIH / NCBI Bookshelf). Prediabetes. NBK538537