Continuous glucose monitoring (CGM) automatically measures the glucose content in the tissue fluid every few minutes and displays it in real time. In contrast to classic blood sugar measurement with your finger, CGM provides a complete 24-hour profile including trend arrows and alarms if values are too high or too low.
How it works
A small sensor with a fine needle is stuck under the skin (usually upper arm or stomach) every 7-14 days. The sensor measures the glucose concentration in the tissue fluid and sends the data wirelessly to a smartphone, an insulin pump or a separate receiving device. Modern systems also display the direction and speed of glucose changes.
Types of CGM systems
| Type | Function | Examples |
|---|---|---|
| Realtime CGM (rtCGM) | Permanent display with alarms | Dexcom G6/G7, Guardian Connect |
| Intermittent Scanning CGM (isCGM) | Data can only be accessed when scanning | FreeStyle Libre 2/3 |
| Integrated CGM (iCGM) | Directly connected to insulin pump | Dexcom with Tandem, Medtronic Guardian |
Advantages
- Early detection of hypo- and hyperglycemia
- Reduction of severe hypoglycemia by up to 50%
- Better HbA1c values with fewer fluctuations
- More safety and quality of life, especially at night and during sports
Indications
CGM is particularly recommended for:
- Type 1 diabetes
- Frequent hypoglycemia or hypo-unawareness
- Insulin pump therapy
- Pregnancy with diabetes
- Children and adolescents with diabetes
Further information:
→ Diabetes mellitus – knowledge and overview
→ Why hyporest
→ Insulin pump therapy (CSII)
Sources
- German Diabetes Society (DDG). S3 guidelines “Technological aids”. As of 2025. Available at: www.deutsche-diabetes-gesellschaft.de/leitlinien.
- American Diabetes Association. Standards of Medical Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1). Available at: diabetesjournals.org.
- Robert Koch Institute (RKI). Federal health reporting – diabetes mellitus in Germany. Berlin 2024.
- International Diabetes Federation (IDF). IDF Diabetes Atlas. 11th edition. Brussels 2025. Available at: diabetesatlas.org.
Important note:
The information in this encyclopedia article is intended solely for general and non-binding information. They do not replace medical advice, diagnosis or therapy. If you have any health questions or complaints, please always consult a doctor or qualified healthcare professional. The content was created with the greatest possible care, but errors cannot be completely ruled out.
Last updated: February 26, 2026
