CGM Sensor Placement, Daily Care and Troubleshooting
Where you wear a CGM matters. The permitted application site depends on the model, age indication and regional instructions. A photograph showing a sensor on an arm does not prove that every sensor can be applied there.
Use the instructions supplied with your specific product and arrange a demonstration if you are unsure. This guide is a checklist for preparing and troubleshooting, not a replacement for the applicator procedure.
Before applying a new sensor Check the model, expiry, packaging and required display device. Install the correct app and verify phone compatibility before opening sterile components. Keep the identifying labels needed for setup and support.
Choose an approved site, prepare the skin as instructed and let it dry. Avoid applying over irritated skin or locations the manual excludes. Rotate sites according to the instructions. Do not improvise a new position because an online video shows someone doing so.
Everyday wear and skin comfort Consider clothing, belts, bags and sleeping positions when choosing among approved sites. Follow the manufacturer’s advice on adhesives and any optional overpatch. More adhesive is not automatically better, especially if it irritates the skin or covers parts that must remain exposed.
If you develop persistent redness, swelling, pain or a suspected retained sensing element, seek medical advice. Do not reinsert a sensor that has come off or try to extend its session beyond the approved instructions.
Water, heat and storage Water resistance has specified limits. It is not permission for unlimited swimming, hot baths or every water activity. The reader and phone may also have different water limits from the sensor.
Check storage requirements before travel or delivery. For example, Dexcom’s G6 guidance gives a sensor range of approximately 2–30°C and warns against a hot parked car or freezer. Use the limits printed for your own sensor, especially during Pakistan’s hot weather.
Signal loss and missing readings First read the app’s message. Check power, Bluetooth, permissions and the required distance between sensor and display. Follow the manufacturer’s troubleshooting sequence. Avoid ending a sensor session, deleting an app or repeatedly pairing devices unless the instructions call for it, because those actions can affect an active session.
Use your backup monitoring plan while readings are unavailable. A promise that stored data may synchronize later does not mean live alerts were available during the interruption.
Unexpected low readings overnight Pressure on a sensor can affect readings in some systems, as Dexcom explains. Do not assume every overnight low is caused by sleeping on the device. If the reading and symptoms disagree, follow the meter-confirmation and treatment instructions for your system and care plan.
Prepare for replacement and support Keep the sensor identifier, start date, screenshots of error messages and a brief description of the issue. Ask the seller which information is required for a replacement assessment. Check replacement CGM sensor listings early enough to avoid a preventable gap in monitoring.
Related guides
CGM vs Glucometer: Why Readings Differ and When to Check
CGM Apps, iPhone Compatibility, Data Sharing and Privacy
Sources
Dexcom: When sensor and meter readings differ
Accu-Chek Pakistan: SmartGuide sensor FAQs
Prepared by CGM Pakistan. Sources checked 8 November 2026. This educational guide has not been independently reviewed by a clinician. Follow the instructions for your supplied device and your healthcare professional’s advice.