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Tips and Hints for Using Your New CGM

If you’ve been using a CGM to help manage your type 2 diabetes, you already know how valuable it is. While the CGM is a powerful tool to manage glucose levels, you might encounter challenges with adhesive or the glucose level display. Read on for tips and hints that can help.
Remember that individual experiences vary. You should always consult your CGM product guide for information.

Having trouble keeping the CGM sensor adhesive stuck to your skin?

CGMs use medical adhesive to keep the sensor in place for 10-day wear. But sometimes, the adhesive starts peeling away sooner than it should.

Having medical adhesive tape on hand can help you secure the adhesive patch for the remainder of sensor wear.

Cut the adhesive patch into strips to tape around the corners of the sensor adhesive; or cut a hole in the adhesive patch to fit over the transmitter. Do not cover the transmitter or sensor with tape.
If you regularly have trouble keeping the sensor on, try prepping the area before you apply it. Clean the site with an alcohol pad or wipe and let the area dry completely. You can try a liquid adhesive for extra stickiness. Liquid adhesive can be applied directly to the skin or to the sensor adhesive patch – just be sure any liquid you apply to the skin or the sensor adhesive does not cover the sensor area.

Not getting glucose readings on your smart phone?

If your smart phone is not displaying your glucose readings, be sure your Bluetooth is on and connected to your CGM system, and open the CGM display app on your smart phone.

Keep the app running in the background at all times.

If you’re not getting a glucose reading, your smart phone may be too far away from your transmitter (the small, removable device that snaps onto the sensor). Or it may be that something is interfering with the signal between the transmitter and the smart phone, such as the wall or water.
Move the transmitter and smart phone within 20 feet of each other. It may take up to 30 minutes for the smart phone to begin displaying glucose readings.

If you are still having challenges, these tips may help:

  • Turn your phone’s Bluetooth off and on. Wait 10 minutes to see if the signal returns.
  • Restart the smart phone and reopen the CGM display app.
  • Close all other background apps on your smart phone.
  • Make sure your phone is charging or charged as some smart phones will turn off Bluetooth while in a low power mode.

Still having issues? Review your CGM User Guide for troubleshooting tips.

Worried the sensor insertion process will hurt?

Today’s CGMs are relatively painless to insert. But for some, there can be a little anxiety about having to insert a new sensor.

There are a few tips that can help:

  • Try wearing headphones and listening to a favorite song or music. Often, it’s the sound of the auto-injector device that causes anxiety.
  • Ask a loved one to do the insertion for you. Sometimes letting someone else do it allows you look away.
  • Build in a small reward for completing a sensor change such as enjoying a small treat, an episode of your newest bingeworthy TV show, or a quick dance party with your family.
  • Ask your health care provider about applying numbing cream to the area.

Worried about accuracy with your CGM reading?

If you compare a CGM reading to a fingerstick, you will likely see two different numbers. It’s common for a blood glucose reading and a CGM reading to be a little different.

Consult the user guide for your CGM to learn more about acceptable variability in readings between a CMG reading and fingerstick.
Note that CGMs may have more variability during the first day a new sensor is inserted. Generally, the match should get closer over the first 24 hours.

There may be times that direct pressure on a CGM sensor can affect glucose readings. If pressure is on the CGM (like when sleeping at night), a false “compression low” may result. The match should get closure after pressure is relieved.Some CGMs, like the Dexcom G6 CGM System, are FDA-permitted to make diabetes treatment decisions without confirmatory fingersticks or calibration. But, if you have symptoms or expectations that do not match your CGM reading, it is recommended that you also do a fingerstick.

Make sure if you are doing a fingerstick with a blood glucose meter, your test strips are stored as directed and not expired. Your hands should be cleaned and completely dried prior to the fingerstick. Some blood sugar meters may also require routine calibration.

CGMs like the Dexcom G6 do not require calibration. You should review your system’s User Guide before calibrating your CGM. If the sensor is requiring any sort of calibration, it will continue to require the calibration at least every 24 hours.

Some people find certain areas in their body for CGM placement seem to work better than others.
Talk to your health care provider for more tips.

Need help with your Dexcom G6 continuous glucose monitor (CGM)? Check out our list of quick tips to help troubleshoot common issues you may have.

Signal Loss or Poor Signal 

First, be sure to check that your phone’s Bluetooth is turned on.  Then turn the Bluetooth off and on.  Wait 10 minutes.
Restart the smart device and reopen the Dexcom app, be sure to close all background apps.

Make sure your smart device is charging or fully charged. 

Low power mode on smartphones will turn off Bluetooth.

Always keep your phone within 20 feet of the sensor.

The transmitter holds 10 minutes of glucose data.  After 10 minutes, data points will drop and there will be gaps in the CGM trend graph.  In general, this means the phone needs to be in the same room as you.

Make sure the signal is not blocked.

Bluetooth is unable to transmit through or around water, cement, steel walls, or other thick barriers.

Sensor signals can be blocked by body tissue because the body is mostly water. 

For example – if the sensor is on the side of an abdomen that protrudes on one side of the body, the signal may not be able to reach a phone kept in a pocket on the opposite side of the body.  Solve this by keeping the phone on the same side of your body as the sensor.
Be sure to clean the back of the transmitter with an alcohol wipe each time before attaching it to a new sensor.

Sensor Not Found or Sensor Loss

If your CGM isn’t picking up sensor signals, wait at least 10-15 minutes after ending a sensor session before trying to start a new session.
Store sensors in a dry place where the temperature remains between 36-86 °F.

Be sure to check if the correct transmitter serial number was entered in the app. The transmitter serial number is found on the back of the new transmitter and on the transmitter box.  A new serial number must be entered in the app each time the transmitter is replaced.

Dropped glucose data points are the first sign that a sensor may be failing prematurely.

Some sensors can have faulty manufacturing.  A sensor that stops giving readings before the 10-day session is completed may be returned to Dexcom for replacement.

Having Difficulty Connecting a New Transmitter to Your Phone or Device

If you are experiencing difficulties connecting a new transmitter to your device, try to remove the transmitter info from your Bluetooth.

Sensor Detaches Before the 10-Day Session Has Ended

Be sure to remove all paper backing before inserting the sensor.

Hold inserter firmly against the skin for 30-60 seconds before pressing the inserter button.  Immediately after insertion, rub firmly three times over the entire patch and smooth out any wrinkles.

It’s important to prep the skin for the sensor to adhere well.

Here’s how:
  • Your sensor site (the location where the sensor is placed on the body) should be flat, clean, and completely dry before you insert the sensor.
  • Scrub the site thoroughly with an alcohol wipe and let dry.
  • Apply sensor patch to an area with as little hair as possible.
  • Shave hair on the area where the sensor is to be applied.
  • Change to a new site with every sensor session.
  • Remove any residue from past sensors with alcohol wipes or with an adhesive remover such as Unisolve, Detachol or Tac Away.

It may take time for the patch to fully dry and stick since skin types vary. During that time, keep your skin dry and avoid engaging in activities that may make you sweat.
If you insert a new sensor before bed, make sure the warmup period is complete before going to sleep.

Additional Application Tips 

Make sure you apply the sensor to an appropriate body area. Note that the Dexcom sensor has only been tested for accuracy in the abdomen.

The sensor is not intended to be worn on the back of the arm as it may not read accurately or stay attached in this area.
  • Avoid placing the sensor patch where the skin folds when you bend.
  • Avoid placing the sensor underneath a waistband.
  • As a rule of thumb, apply the sensor where at least ½”-1” of fat (not skin) can be pinched between thumb and forefinger.

Apply adhesive supplement or under the patch, avoiding the spot where the needle inserts. Then, let dry.
Skin-Tac wipes or solution – may also daub or wipe solution under any loose section of the skirt.  The product becomes stickier as it dries.
Mastisol solution – same as above.
Dexcom overpatch – this is a clear plastic cover shaped to be placed over the sensor which helps hold any loosened fabric onto the skin.  The overpatch is effective for securing the sensor when swimming, both in chlorinated and saltwater.
You can order free overpatches at

Skin Reactions
Applying a barrier for protection underneath the sensor patch can help prevent redness, itching and skin erosions due to adhesive sensitivity.

A chart showing benefits and professional tips for various adhesive supplements, adhesives, tapes and protective barriers may be found at:

Consider joining a user group such as the Facebook Group: “Dexcom and Libre Rash” to explore ideas and suggestions that have worked for other Dexcom users experiencing skin reactions.

What works best for one person may not work well for everyone. You may need to try several different products or methods to figure out what works best for you.

Want to get the most from your CGM?

Wearing a CGM can be empowering. It can help you see what’s leading to spikes and can be rewarding to see what’s keeping you steady.

To get the most from the CGM, start learning from it. Connect certain actions with your glucose levels.

For example, monitor what happens after you eat breakfast for a few days. Do your glucose levels spike out of range? If they do, you know it’s an opportunity to make a change or two. Maybe it’s replacing a breakfast cereal with oatmeal, swapping out orange juice for water or fat-free milk, or starting breakfast with a protein first, such as a scrambled egg, before you have toast.

Watch what happens when you take the stairs instead of an elevator, or do yoga before dinner? It might surprise you to see that a short walk around the block in the evening can have a positive impact on your glucose levels overnight.

Watching your CGM arms you with useful information about your actions. With it, you’ll be able to incorporate small lifestyle changes that can have a big impact.
Another quick tip – the phone can be turned to the landscape orientation to show more data.

Don’t Use a CGM But Considering One?  

Find out if you’re eligible for a free CGM from Level2 today.