Endocrinology• Updated 21 October 2026
Continuous Glucose Monitoring (CGM)
A small sensor worn on the skin that measures glucose every few minutes for up to two weeks.
Results: Continuous Specimen: Fluid under the skin
Quick Summary
Primary Purpose
To see glucose patterns, especially for people on insulin.
What It Measures
Glucose trends and time in range.
Preparation
Follow the device instructions.
Overview
CGM shows highs and lows that finger-pricks can miss.
Time in range is a useful target.
What It Measures
Glucose trends
Throughout the day and night.
Time in range
Percentage in target.
How It's Performed
- 01
Apply
Sensor on the arm or tummy.
- 02
Wear
For the sensor's lifetime.
- 03
Review
Data on a reader or phone.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Blood Glucose Test(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Continuous glucose monitoring and hybrid closed loop for diabetes(opens in a new tab) · NHS