Living with a CGM: phones, accuracy, travel and fixes
How readings reach your phone or reader, what accuracy numbers mean, airport screening, medical scans and what to do when a sensor fails.
Written by PlanScout teamReviewed by PlanScout Internal Review TeamLast reviewed Oct 25, 20264 sourcesHow we make money
Phones and readers
- Most CGM apps work only on certain phones and phone software. Check the maker's list before you upgrade your phone.[1],[2]
- Abbott advises turning off automatic phone software updates and checking its list first.[1]
- Keep alarms allowed in your phone's settings. If they are blocked, you can miss a low sugar alarm.[1]
What accuracy numbers mean
- Makers report accuracy as mean absolute relative difference (MARD). It is the average gap between the sensor and a lab test.[3]
- A lower MARD means closer to the lab on average. It does not promise every reading will be close.[3]
- Some sensors can read wrong if you take a lot of vitamin C. Check your device's safety page.[1]
Airports and travel
- Tell the Transportation Security Administration (TSA) officer where your glucose monitor is before screening starts.[4]
- You will not have to take off a device attached to your body.[4]
- A device you have taken off may go through the X-ray. Tell the officer if you don't want that, and they will screen it another way.[4]
- Pack extra sensors in case one fails or falls off on the trip.[1]
Medical scans and treatments
When something goes wrong
- If a sensor stops working and you have no spare, use another way to check your sugar until you replace it.[1]
- The app may shut a failing sensor off and tell you to replace it. Call the maker's customer service line.[1]
- Clean and dry the skin before you put on a sensor. It helps the sensor stay on for its full wear time.[1]
Prices and suppliers near you
Enter your ZIP code in the price box above to see how many suppliers near you billed Medicare for CGM. Or search suppliers by ZIP.
More in this guide
- Continuous glucose monitors: overviewHow a glucose monitor works and who Medicare covers. See what you pay in your ZIP code. Then see how Dexcom, Libre, MiniMed and Eversense differ.
- Does Medicare cover a CGM? Who qualifies, step by stepThe five Medicare rules in plain words. How you can qualify without insulin. And the visit you need every six months to keep it.
- What a CGM costs with MedicareWhat you pay with Original Medicare. What the monthly supply payment buys. And why using only your phone can cost you.
- How to get a CGM, and how to switch brandsWho writes the order, how to pick a supplier, what training to expect, and what to know before you switch to another CGM brand.
Reviewed & sourced
- Reviewer
- PlanScout Internal Review Team. Checks facts and plain-English accuracy; has no say in how results are ordered.
- What was checked
- Owner sign-off for the PlanScout Internal Review Team: Medicare coverage rules, costs and brand facts against the cited sources
- Last reviewed
- Oct 25, 2026
- Next review
- Before Jan 1, 2027 (new plan year), or sooner if Medicare changes a rule.
- Corrections
- See something wrong? Tell us. We fix confirmed errors within 2 business days and note the change in the page's change log.
- Change log
- Oct 25, 2026: First published and reviewed.
Sources (4)
- Abbott: FreeStyle Libre important safety information (retrieved Oct 25, 2026)
- Dexcom: Dexcom G6 CGM system (retrieved Oct 25, 2026)
- Dexcom: How is Dexcom G7 15 Day different from Dexcom G7? (retrieved Oct 25, 2026)
- Transportation Security Administration: Disabilities and medical conditions (retrieved Oct 25, 2026)