How it works
A thin sensor worn on the arm or abdomen measures glucose in the fluid under the skin every few minutes and sends readings to a phone or reader. Most sensors last 10 to 15 days, depending on the device.
What you can see
- Your current glucose and which way it is heading
- Alerts for highs and lows, including at night
- Time in range: the share of the day between 70 and 180 mg/dL
For many adults with diabetes, a common goal is more than 70% of time in range and less than 4% below 70 mg/dL. Targets are different in pregnancy, in older adults and for people at high risk of lows.
Who may benefit most
- People with type 1 diabetes
- Anyone using insulin
- People with frequent or night-time lows
- Those with swinging sugars that HbA1c does not explain
- People for whom HbA1c is unreliable, such as with anaemia or kidney disease
- People who want a short trial to see how food and activity affect them
Limits
- Sensor readings lag behind blood by several minutes
- A finger-prick is still needed if symptoms do not match the reading
- Cost, and occasional skin irritation from the adhesive
- It does not diagnose diabetes
Getting the most from it
Look at patterns over two weeks rather than reacting to each number, and review the report with your doctor. HbA1c and CGM work best together.
This guide is general information and is not a substitute for a consultation.