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Fasting blood sugar — reference ranges
Glucose measured after at least 8 hours with nothing but water — usually first thing in the morning before breakfast.
| Bande | mmol/L | mg/dL | Ce que cela signifie |
|---|---|---|---|
| Normal | 4.0-5.5 | 72-99 | The expected fasting range in a healthy adult. |
| Impaired fasting glucose | 5.6-6.9 | 100-125 | "Prediabetes": higher than normal but not diabetes. A signal to retest and look at the whole picture. |
| Diabetes | 7.0 or above | 126 or above | On two separate tests, a fasting value of 7.0 mmol/L or higher meets the WHO diagnostic criterion for diabetes. |
Le lire en contexte
Fasting is the reading most people know because it is the easiest to standardise: nothing but water for at least eight hours, measured before breakfast. One slightly high morning value is not a diagnosis — illness, a bad night, stress and some medicines raise fasting glucose, and the WHO criterion asks for two separate test days.
The "dawn phenomenon" — a normal rise in the last hours of sleep — is why the fasting value is not the same as the true 24-hour average: in some people the body releases glucose to start the day, and the morning reading overshoots.
Quand voir un clinicien
- A fasting value at or above 7.0 mmol/L on two separate days — see a clinician for a formal test.
- Repeated values in the 5.6-6.9 range, together with weight, family history or age risk factors — worth a conversation.
- Any value that keeps creeping up month over month, even inside the normal range.
Référence seulement, pas un diagnostic. Les seuils de cette page sont des valeurs OMS et ADA au niveau population ; votre clinicien interprète vos propres chiffres contre votre histoire, vos médicaments et d’autres tests. Si une valeur vient avec des symptômes, ou continue de bouger dans le mauvais sens, c’est le signal d’agir — pas cette page.