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Continuous glucose monitors (CGM) — reference ranges
A small sensor under the skin reads glucose every few minutes and draws the whole curve — not just the moments you prick. A different picture: shape, not points.
| Bande | mmol/L | mg/dL | Ce que cela signifie |
|---|---|---|---|
| Time in range | 3.9-10.0 mmol/L | 70-180 mg/dL | The international consensus target: for most adults with diabetes, at least 70% of the day inside this band. |
| Below range | under 3.9 | under 70 | The consensus target is under 4% of the day below 3.9 mmol/L, and under 1% below 3.0. |
| Above range | over 10.0 | over 180 | The consensus target is under 25% of the day above 10 mmol/L. |
Le lire en contexte
For someone without diabetes, a CGM mostly shows a flat line between 4 and 7.8 mmol/L with modest, brief bumps after meals. The useful habits the curve exposes: which meals spike and crash, what a walk after eating does to the peak, and what alcohol does to the overnight line.
The sensors read the fluid between cells, not blood, so they lag blood glucose by 5-15 minutes and read lower during rapid change — when the trend arrow points down, the real blood value is usually lower than the screen. Finger-prick checks stay the reference for decisions.
A CGM is a trend tool, not a diagnostic one: the wearer's own clinician sets the targets, and the consensus time-in-range numbers above are for adults with diabetes, not a scorecard for healthy wearers.
Quand voir un clinicien
- CGM values repeatedly above 11 mmol/L or below 3.9 — bring the report, not just the feeling, to a clinician.
- A hypo with a flat or rising arrow that stays low despite treatment — treat first, review after.
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.