Where CGM Helps
Reviewed by CDE Mehandi Sharma · Updated
A continuous glucose monitor is a sensor worn on the skin that reads glucose all day and night. In monogenic diabetes it is best thought of as a short-term diagnostic tool rather than an ongoing expense.
Where it earns its place.
- During a treatment change — coming off insulin, or starting a sulfonylurea — when you need to see what is happening rather than sample it a few times a day.
- When lows are suspected on a sulfonylurea but fingersticks keep missing them, particularly overnight.
- To characterise the post-meal pattern in HNF1A or HNF4A-MODY, where the rise after eating is the defining feature.
- In pregnancy, where targets are tighter and the stakes higher.
Where it is not needed. Untreated GCK-MODY. If glucose is mildly raised, stable, and nobody intends to change treatment, continuous data answers no open question — and it can make a benign pattern look alarming.
Cost is the practical limit in India. Sensors are a recurring out-of-pocket expense, so two weeks used to answer a specific question is far better value than continuous use with no question in mind.
If you are considering one, decide the question first and agree with your doctor what you are looking for. A sensor worn without a purpose mostly produces data nobody acts on.