Dexcom G7 / Stelo CGMs

Dexcom G7 and Stelo CGM: The Complete Guide for Parents, Caregivers, and Healthcare Professionals | PediaDevices

1 What is a CGM? A Simple Introduction

A CGM (Continuous Glucose Monitor) is a small device that you wear on your skin. It checks the sugar (glucose) level in your body all day and all night, without needing finger prick tests. The device sends these readings to a phone or a separate screen every few minutes.

Dexcom is a company that makes two such devices: the Dexcom G7 and the Stelo. Both are glucose monitors, but they are made for different people and used in different ways. This guide explains everything about both devices in simple, clear language.

💡 Key Point
A CGM is NOT the same as a regular blood glucose meter (the one that uses finger pricks). A CGM reads glucose from the fluid under your skin. The readings may be slightly different from a finger prick test, and that is normal.

2 Purpose and Where These Devices Are Used

The main purpose of a CGM is to help people with diabetes manage their sugar levels without constant finger prick tests. It helps users and their doctors see patterns - like when sugar goes too high or too low - and make better decisions about food, medicine, and activity.

Where Are They Used?

  • Hospitals and clinics - Doctors use CGM data to adjust treatment plans.
  • At home - Patients and parents monitor glucose daily, day and night.
  • Schools and activity centers - Parents and teachers can remotely watch a child's glucose through the Follow app.
  • Sports and travel - CGMs work while swimming, exercising, and flying.

Who Needs a CGM?

ConditionDexcom G7Stelo
Type 1 DiabetesYesNo (not for insulin users)
Type 2 Diabetes (on insulin)YesNo
Type 2 Diabetes (not on insulin)YesYes
PrediabetesYes (with prescription)Yes
Gestational DiabetesYesNo (not approved in pregnancy)
General glucose awareness (no diabetes)Not indicatedYes (adults 18+)

3 Types: Dexcom G7 vs Stelo

Dexcom makes two glucose monitoring devices. They look similar but serve very different purposes. Understanding the difference is important before choosing one.

Dexcom G7

Prescription Required

Type: Full medical CGM

Age: 2 years and older

Wear time: Up to 10 days (+ 12 hr grace period)

Alerts: Yes - high, low, and urgent low alerts

Insulin pump: Can connect to certain pumps

Best for: Anyone with any type of diabetes who needs real-time alerts and clinical-grade monitoring

Dexcom Stelo

No Prescription Needed

Type: Glucose biosensor (lifestyle tool)

Age: 18 years and older only

Wear time: Up to 15 days

Alerts: No alerts or alarms

Insulin pump: Cannot connect

Best for: Adults with type 2 diabetes (not on insulin), prediabetes, or those who want to understand how food and lifestyle affect glucose

⚠ Important Difference
Stelo does not send alerts when glucose is dangerously low. This makes it unsafe for anyone who uses insulin or who has a history of serious low blood sugar (hypoglycemia). If your child or family member is on insulin, they must use the Dexcom G7, not Stelo.

Dexcom G7 Sub-Types

FeatureDexcom G7 (Standard)Dexcom G7 15 Day
Age group2 years and older18 years and older
Wear timeUp to 10 days (+ 12 hr grace)Up to 15 days (+ 12 hr grace)
MARD (accuracy)8.2%8.0%
Sensors per monthAbout 3About 2
App and receiverSame as G7 15 DaySame as G7 Standard
💡 What is MARD?
MARD stands for Mean Absolute Relative Difference. It measures how close the CGM reading is to the real blood glucose level. A lower number is better. For example, a MARD of 8% means the reading is usually within 8% of the real value.

4 How Do They Work? The Science Made Simple

Both the Dexcom G7 and Stelo use the same basic technology. Here is how it works, step by step:

1
A tiny sensor goes under the skinA very small, thin wire (thinner than an insulin needle) is placed just under the skin. It sits in the fluid between your cells. This fluid is called interstitial fluid.
2
The sensor reads glucoseThe sensor wire has a special chemical called glucose oxidase. It reacts with glucose in the fluid and turns it into an electrical signal.
3
The signal is sent to your phone or receiverThe small transmitter (built into the sensor patch) sends the glucose reading wirelessly to your phone app or a separate Dexcom receiver. This happens automatically every 5 minutes.
4
You see your glucose on screenThe app or receiver shows your current glucose number, a graph of how it has changed, and an arrow showing if it is going up, down, or staying the same.
💡 CGM vs Blood Glucose Meter
A CGM reads glucose from the fluid under the skin. A blood glucose meter reads glucose directly from blood (via a finger prick). These two numbers are not always the same. There can be a small time delay of about 3 to 5 minutes with the CGM. If your symptoms do not match what the CGM shows, always use a blood glucose meter to confirm.

5 Step-by-Step User Guide

Part A: Setting Up the Dexcom G7 App

1
Download the appGo to the App Store (Apple) or Google Play Store (Android). Search for Dexcom G7. Download and open the app.
2
Create or log into your accountFollow the on-screen steps. If you are setting this up for a child, create a dependent account for them.
3
Enable BluetoothMake sure Bluetooth is turned on in your phone settings. The app needs Bluetooth to talk to the sensor.
4
Turn on notificationsAllow the app to show alerts on your phone's lock screen. Apple users must also turn on Critical Alerts.

Part B: Inserting the Dexcom G7 Sensor

✅ What You Need
One Dexcom G7 sensor (with applicator already attached), one overpatch (included in box), one alcohol wipe, clean dry hands.
1
Choose the right spotAdults (18+): Back of the upper arm or lower belly (abdomen). Children ages 2 to 17: Back of the upper arm only. Children ages 2 to 6: Back of the upper arm OR upper buttocks. Pick a spot with enough soft tissue (fat) - avoid bones, tattoos, or irritated skin.
2
Clean the skinWash your hands with soap and water. Wipe the chosen spot with an alcohol wipe. Wait at least 10 seconds until it is completely dry.
3
Prepare the applicatorOpen the sensor package. Unscrew the cap from the applicator. Do not touch anything inside the applicator.
4
Insert the sensorPress the applicator firmly against the skin until the clear safety guard pushes in. Then push the button on the side. Remove the applicator - the small sensor and sticky patch will stay on your skin.
5
Secure the patchRub firmly around the sticky patch 3 times. Press gently on the sensor for 10 seconds to make a good seal with the skin.
6
Apply the overpatchPeel off the clear liners one at a time. Do not touch the white sticky area. Use the colored tab to place the overpatch over the sensor. Rub around the edges. Remove the colored liner.
7
Pair with your phoneOpen the Dexcom G7 app. Enter the 4-digit pairing code found on the applicator you just used (or take a photo of it). Keep your phone within 20 feet of the sensor.
8
Wait for warm-upThe sensor needs about 30 minutes to warm up and start giving readings. Do not remove it during this time. Keep the area as dry as possible during the first 12 hours.

Part C: Using the Dexcom G7 Receiver (Optional)

You can also use a handheld Dexcom receiver instead of (or in addition to) a smartphone. The receiver has 4 buttons and walks you through setup. Press and hold the select button for 3 seconds to turn it on. Follow the on-screen instructions to set date and time, watch safety videos, and pair with your sensor using the same 4-digit code.

Part D: Setting Up the Stelo Biosensor

Stelo uses its own app called Stelo by Dexcom. Download it from the App Store or Google Play. The setup and insertion steps are very similar to Dexcom G7. The main difference is that Stelo has a 30-minute warm-up time and the app is simpler, focused on lifestyle insights rather than clinical alerts. Stelo connects to Apple Health and Google Health Connect for extra tracking.

Part E: Replacing the Sensor

When a sensor reaches the end of its wear time, the app will tell you. Peel off the overpatch first, then carefully lift the sensor patch from the skin. Clean the area. Insert a new sensor in a different spot to let the skin rest. Always rotate your insertion sites.

6 Precautions and Dangers

🛑 Do NOT Use If:
  • You are on dialysis (both G7 and Stelo).
  • You use insulin and are considering Stelo - it has no low-sugar alerts.
  • You are pregnant and considering Stelo - it is not approved during pregnancy.
  • You are under 18 years old and considering Stelo - it is for adults only.
  • You have a known allergy to any material in the sensor or adhesive.

Medical Imaging

Remove the Dexcom G7 sensor before any MRI, CT scan, or diathermy (high-frequency heat) treatment. The device has not been tested with these machines. It may give wrong readings or get damaged. Tell your doctor you are wearing a CGM before any scan.

Skin Risks

  • Skin irritation or rash - The adhesive patch can cause redness, itching, or a rash in some people. This is more common with sensitive skin.
  • Infection - Although rare, any break in the skin has a small chance of infection. Always clean the skin before inserting a sensor.
  • Scarring - Using the same spot every time can cause scarring. Always change your insertion site.

Medication Interference

Taking acetaminophen (paracetamol) - found in medicines like Tylenol - can make your CGM reading appear higher than it really is. The higher the dose, the bigger the difference. Ibuprofen (NSAIDs) does not cause this problem and is safe to take with Dexcom devices.

Compression Lows (Sleeping)

If you sleep on the side where the sensor is placed, your body weight can press on it and cause a falsely low reading. This is called a compression low. If you get a low alert at night but feel fine, check with a blood glucose meter before taking any action.

Choking Hazard

The sensor, transmitter, and packaging contain small parts. Keep all packaging and unused parts away from very young children. The transmitter kit box also contains a small magnet - do not let young children swallow it.

⚠ Travel and Security
You can fly and go through airport security while wearing a CGM. You can pass through metal detectors and body scanners. However, after going through security scanners, consider checking your glucose with a finger prick meter until you are away from the scanning area, as a precaution.

7 Frequently Asked Questions

Can my child (age 2) use Dexcom G7? +

Yes. Dexcom G7 is approved for children aged 2 years and older with any type of diabetes. For children aged 2 to 6, the sensor can be placed on the back of the upper arm or the upper buttocks. For children aged 7 and older, use the back of the upper arm only.

Can my child use Stelo? +

No. Stelo is only approved for adults aged 18 and older. If your child needs glucose monitoring, talk to your doctor about Dexcom G7.

Is the sensor waterproof? Can my child swim? +

Yes. Both Dexcom G7 and Stelo sensors are waterproof. They can be submerged under 8 feet (about 2.4 meters) of water for up to 24 hours when properly installed with the overpatch. Swimming, showering, and bathing are all fine.

Do I still need a blood glucose meter (finger prick)? +

Yes, keep one nearby. If the CGM reading does not match how you feel, or if symptoms suggest low or high sugar but the CGM shows normal, use a blood glucose meter to confirm. Always use the meter reading to make treatment decisions in such cases.

How accurate is the Dexcom G7? +

The Dexcom G7 has a MARD of 8.2% (the G7 15 Day has 8.0%). This means it is among the most accurate CGMs available. However, no CGM is 100% perfect. Always confirm with a finger prick if you are unsure.

Does Stelo need a prescription? +

No. Stelo is an over-the-counter (OTC) product. You can buy it online or in stores without a doctor's prescription. However, always talk to your doctor before changing any diabetes management routine.

Can Dexcom G7 connect to an insulin pump? +

Yes. Dexcom G7 can work with certain insulin pumps (such as Tandem and Omnipod) to create what is called an Automated Insulin Delivery (AID) system. Stelo cannot connect to any insulin pump. Check with your doctor about compatibility.

Can other people see my child's glucose readings? +

Yes. The Dexcom Follow app lets up to 10 people remotely see glucose data and receive alerts. This is very useful for parents when children are at school or a friend's house. It requires an internet connection.

How long does it take to insert the sensor? +

The actual insertion takes just a few seconds. The full process, including cleaning the skin, inserting, applying the overpatch, and pairing with your phone, takes about 5 to 10 minutes.

Is inserting the sensor painful? +

Most people say it is painless or causes only very mild discomfort. Studies show that about 94% of users reported the insertion as painless. The sensor wire is very thin - thinner than an insulin injection needle.

What happens if the sensor falls off early? +

The sensor will stop sending readings. If this happens, you will get a signal loss alert in the app. Use a blood glucose meter until you can insert a new sensor. Apply the overpatch correctly and keep the skin dry for the first 12 hours to help prevent this.

Can I store unused sensors in the fridge? +

Yes. Sensors can be stored at room temperature or in the fridge, between 2 degrees C and 30 degrees C (36 degrees F to 86 degrees F). Do NOT store them in the freezer.

8 How to Keep the Device Safe

Sensor Care

  • Always use the overpatch included in the box. It keeps the sensor in place.
  • Keep the sensor area dry for the first 12 hours after insertion to help the patch stick well.
  • After the first 12 hours, gently pat the area dry if it gets wet - do not rub.
  • If the overpatch starts to peel, trim the edges and secure with medical tape.
  • Rotate your insertion site every time you put on a new sensor. Never use the same spot twice in a row.
  • Do not apply the sensor over tattoos, scars, irritated skin, or bones.

Phone and Receiver Care

  • Keep your phone or receiver within 20 feet (6 meters) of the sensor at all times. G7 with upgraded Bluetooth extends this to about 33 feet (10 meters).
  • Keep your phone battery charged. If the battery dies, you will not get alerts.
  • Do not modify, open, or repair the sensor, transmitter, or receiver yourself.
  • If the receiver case is cracked or damaged, stop using it. It could be a safety or electrical hazard.
  • Before updating your phone's operating system, check the Dexcom website to make sure the new system is compatible.

Storage

  • Store unused sensors in a cool, dry place or in the fridge (not freezer).
  • Check the expiry date on the package before using any sensor.
  • Do not expose sensors to extreme heat or direct sunlight for long periods.
🛑 USB Cable Warning
The charging cable for the receiver should be kept away from young children. It can be a strangulation hazard.

9 Special Notes for Parents and Caregivers

If your child has diabetes and uses a Dexcom G7, here are important things to know:

What to DoDetails
Set up Dexcom FollowDownload the Follow app on your phone. This lets you see your child's glucose and get alerts remotely.
Teach your childChildren aged 7 and above can learn to manage their own sensor with guidance. Younger children need an adult to insert and change the sensor.
Inform the schoolTell teachers about the CGM. Explain that alerts may go off and what they mean. Give them your contact number.
Keep a backup meterAlways have a blood glucose meter (finger prick type) at home, school, and when traveling.
Check the skin regularlyLook at the sensor site every day for redness, swelling, or any signs of infection.
Sensor placement for young kidsFor children aged 2 to 6, the upper buttocks is an approved and comfortable placement option.
💡 About the Follow App
The Dexcom Follow app requires an internet connection to work. If the internet goes down, the follower (parent) will stop seeing updates. This does not affect the sensor itself - it still collects data and sends it to the user's own phone.

10 Notes for Healthcare Professionals

  • Dexcom G7 is indicated for patients aged 2 years and older with type 1, type 2, or gestational diabetes. The G7 15 Day is for patients 18 and older only.
  • Stelo is an OTC lifestyle biosensor for adults 18+ not on insulin and not at risk of hypoglycemia. It is not a clinical decision-making tool.
  • Both devices use factory-calibrated sensors. Routine finger-stick calibration is not required, but optional user-initiated calibration is available on G7.
  • Dexcom G7 integrates with Automated Insulin Delivery (AID) systems including Tandem Control-IQ and Omnipod 5.
  • MARD values: G7 = 8.2%, G7 15 Day = 8.0%, Stelo = 93% accuracy compared to lab blood glucose (as reported by Dexcom).
  • Pediatric sensor placement: Back of upper arm for ages 2+; upper buttocks also approved for ages 2 to 6.
  • The sensor wire is inserted at a 90-degree angle and is shorter than the G6 wire.
  • Warm-up time is approximately 27 to 30 minutes for G7 (compared to 2 hours for previous generation G6).
  • Data can be shared and reviewed in Dexcom Clarity for clinical reporting.

Suggested References and Resources

  • Dexcom Official Safety Information - dexcom.com/safety-information
  • Dexcom G7 User Guide - dexcom.com/guides
  • Stelo by Dexcom Official Site - stelo.com
  • American Diabetes Association Consumer Guide - consumerguide.diabetes.org
  • Garg SK, et al. "Accuracy and Safety of Dexcom G7 Continuous Glucose Monitoring in Adults with Diabetes." Diabetes Technology and Therapeutics, 2022.
  • Welsh JB, et al. Dexcom G7 sensor placement studies. Journal of Diabetes Science and Technology, 2022 and 2024.
  • Laffel LM, et al. "Effect of Continuous Glucose Monitoring on Glycemic Control in Youth With Type 1 Diabetes." JAMA, 2020.
  • International Diabetes Federation (IDF) - idf.org
  • Diabetes Technology and Therapeutics (peer-reviewed journal)
Content Checked and Reviewed by a Pediatrician | Last Updated: January 2025

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