Tips for Using a Dexcom Continuous Glucose Monitor

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Many people with people with diabetes are using a continuous glucose monitor (CGM) to track blood sugar levels and get alerts for high and low blood sugar. One of the most popular makers of CGM devices is Dexcom, which currently offers the Dexcom 5 and newer Dexcom 6 CGM models. I’ve been using a Dexcom 5 for almost a year and have learned some helpful tips to help make your Dexcom CGM more effective for you.


Calibrate your CGM regularly and accurately

Your Dexcom continuous glucose monitor (CGM) is only accurate if you carefully calibrate it. To ensure good results with your CGM:

  • Your CGM sensor will work better if you clean the underside of the transmitter — and your skin — with an alcohol pad before each new insertion.
  • Make sure you calibrate as often as recommended by the manufacturers. I calibrate my CGM twice a day as recommended.
  • Always wash your hands before calibrating your CGM. Dirty hands can affect blood sugar readings


More calibrating tips

  • Avoid calibrating your Dexcom continuous glucose monitor (CGM) when your glucose level is very low or is rapidly changing. Only calibrate when you have a horizontal line, and your blood sugar is stable.
  • Don't calibrate your CGM when you plan to eat, shower, bathe, exercise, or take insulin in the next 15 to 20 minutes.


Use your CGM alarms proactively

If you want to catch your high and low blood sugar levels quickly, set your Dexcom continuous glucose monitor (CGM) alarms more broadly.

For example, I set my CGM’s “low” alarm at 80, so that I can act at that point before it becomes a dangerous hypoglycemic low.

Also, you can change the alert sounds for your CGM alarms. If one alarm sound doesn't get your attention, try switching to a more noticeable sound or tone.


Be careful when correcting a low blood sugar

When you have a low blood sugar level and have done a correction–like taking some juice or glucose tabs—get a finger stick reading before you take any more corrective carbohydrates. The Dexcom continuous glucose monitor can lag from 15 to 20 minutes behind your actual blood sugar, and you are at risk of overcorrecting and making your blood sugar go too high.


Understand and work with your trend arrows

Learn what your Dexcom's trend arrows mean for you. Dexcom gives you arrows pointing straight up (rising quickly), towards the upper right (rising), right (stable), lower right (dropping), and straight down (dropping swiftly). If you know how quickly you would reach hyper- or hypoglycemic blood sugar levels based on the trend arrows, you may be able to make a proactive correction correct with insulin or carbohydrates.


Be aware of the acetaminophen effect

You should be aware that drugs that contain acetaminophen (Tylenol) or paracetamol affect the accuracy of your continuous glucose monitor. If you must take acetaminophen or paracetamol, use your regular glucometer to check blood sugar levels for at least around 12 hours afterward. Also, be careful about combination drugs. One day, I had some unusually high readings after taking cold medicine, only to read the label and discover it contained acetaminophen.


How to keep your sensor attached

There are times when my adhesive patch has started to peel off too soon, and one time the patch and sensor all fell off after a few days. If your patch peels or becomes loose, you can apply specialized patches designed with built-in cutouts for your Dexcom sensor. Two popular brands include:

  • Simpatch adhesive patches, which come in several colors
  • GrifGrips patches, which come in many colors and designs, including hearts, flowers, and butterflies


Tape down your sensor patch

If your patch is peeling, loosening, or tends to fall off, you can use medical/surgical tape to tape it down.

Some popular brands recommended by people with diabetes include StayPut, Durapore, and Tegaderm. Rock Tape brand tape comes in a variety of bright colors.

Make sure that when you tape down your sensor patch, you don’t tape over or on the sides of your transmitter, or you may interfere with the transmitter’s accuracy or ability to transmit.


Use adhesive wipes to help your sensor stick

If your sensor tends to loosen or fall off too soon, you may want to try Skin-Tac Adhesive Wipes before you apply your sensor patch.

After cleaning your skin with alcohol, you use a Skin-Tac wipe on the application area. These wipes make your skin stickier and help the sensor patch adhere better and stay attached to your skin longer. Skin-Tac is also available in a liquid version.


Get more than a week from your sensor

The FDA approves Dexcom CGM sensors for 7-day use, but many people use the same sensor for up to three weeks with no loss of accuracy. I’ve been able to extend the life of my sensor for as long as 18 days before it finally gives out. Here’s how:

  • When you get the “sensor session ending” alert, hit “Stop Sensor,” and then “Start Sensor.” After the two-hour warmup period, calibrate your sensor with the recommended two finger sticks, and your sensor will restart.
  • After a restart, calibrate your CGM regularly to ensure accuracy.
  • If your restarted sensor loosens, use a patch or surgical tape to affix it to your skin.


You can change the location of your sensor

While Dexcom’s manufacturer recommends wearing your sensor on the abdomen, some people find it more convenient or accurate to apply it to the back of the arm, buttocks, or upper thigh – anywhere you can pinch a bit of fat.

If you decide to wear it in one of these alternate locations, calibrate your Dexcom readings to ensure accuracy at that location.

Wild Village/Sugarmate

Use a Dexcom-compatible app

To better use your Dexcom 5 or 6 data, I recommend downloading Sugarmate for IOS or Android. You give Sugarmate access to “follow” your Dexcom data. You can search and enter carbohydrate information for thousands of foods, get a 6-day A1c reading, track different types of insulin, and sync across devices. My favorite feature: Even if you have "Do Not Disturb" on, it calls you at nighttime to alert you to dangerously low blood sugar. (I can sleep through Dexcom alarms, so this is a great service!)