CGM (continuous glucose monitor) pros and cons

If you’re diagnosed as a diabetic, testing blood sugar is a must, especially for Type-1 diabetics because very low blood sugar, which is what Type-1 diabetics deal with frequently, can cause falls, blackouts, a coma, and even death.

There’s several continuous glucose monitoring devices (aka CGM) and systems that test blood sugar around the clock. How it works, is that a sensor is applied to the upper back of the arm, after cleaning that area. The “gun” shoots the sensor into the arm. The sensor stays put with an adhesive glue. The way the sensor is able to give readings is through a needle in the middle of the sensor.

I did research on YouTube and watched many videos on CGMs, and people really seemed to like the convenience of the being able to test their blood sugar by swiping their phone or the reader, which looks like a small phone, near the sensor to get a reading right away.

My doctor recommended a CGM from FreeStyle Libre and called in the prescription to a pharmacy closest to me. After I picked up the two-pack of sensors and the reader, I followed the directions and was surprised by how much putting the sensor on, hurt. It felt like someone punched me in the arm with a thick needle. It stung. Literally. It felt like a bee sting, even several minutes after the sensor was applied. That was a definite negative.

A plus to continuous glucose monitoring, is how easy it is to test blood sugar, but testing became a new obsessive-compulsive habit. I wanted to know how much my blood sugar went up after a meal, how much it went down after a workout, what made it stabilize, what the numbers looked like at night, and what the numbers were, pretty much, every hour of the day.

My husband also decided he wanted to check my blood sugar without telling me. He would grab the reader and swipe it by my arm and would read the results to me. For all of you that have a loved one that wears a CGM, don’t check someone’s blood sugar without permission, it’s invasive and personal; you’re looking at the readings of someone’s fluid inside their body. If the person’s blood sugar is high, you’re going to upset them, and they will think you are blaming them for having high blood sugar.

Everyone’s blood sugar rises during exercise, and after eating food, so higher blood sugar readings are normal. It takes a diabetic’s blood sugar longer to go down and stabilize because Type-1 diabetics have to use synthetic insulin in doses estimated by calculating carbs, looking at portion sizes, and based on how we feel. A healthy pancreas spits out insulin in spurts, but synthetic insulin in given in one large dose, when needed, so it’s impossible to always have healthy blood sugar numbers.

Diabetics use glucose readings to determine if there is a need to take more insulin, to eat more carbs, or to see if we can resume going about our day. It’s really important to have accurate blood sugar readings because excess insulin can cause falls, concussions, stays in the hospital, and even death. Having blood sugar in healthy ranges is crucial because it’s the difference between life, death, and medical problems in the future.

Having accurate blood sugar readings is vital. To verify the reader’s accuracy, the instruction booklet advises to do finger sticks. A finger stick is where you test your blood sugar by inserting a needle into a finger to draw out blood. That blood is then placed, in a droplet, onto a strip. The blood on the strip gets sucked into meter to provide a number, displayed on the meter. Every time I compared the finger stick reading to the CGM reading, the numbers were never the same. Sometimes they were sort of close, ten points off, but sometimes they were extremely far off, by as much as forty-three points.

Under limitations from the company’s website, it says: “Check sensor glucose readings with a blood glucose meter when Check Blood Glucose symbol appears, when symptoms do not match system readings, or when readings are suspected to be inaccurate“ (1).

The entire point of purchasing a CGM is to get accurate readings without having to fingerstick.

What I also didn’t like, was having to wear a medical device, in plain sight, for everyone to see. The sensor looks like a shiny white, flat button. I don’t know why the sensor is not available in shades of tans and browns to make them less obvious.

The sensor is not supposed to get in the way of activities, but I banged it against the wall a few times, and I’m not a clumsy person. Having an object protruding from my body is bound to get hit by a wall. It also hurt a lot more when I hit my arm, with the sensor in it.

The burning that I mentioned subsided, but not altogether. The area under and around the sensor stung and itched. I started to panic, wondering if the skin was dying under the sensor since it didn’t have access to free flowing air and could be undergoing necrosis.

After three days of use with the CGM, I wanted the sensor off my body, but it wouldn’t come off. My husband had to take tweezers to get underneath the sensor and pull it off my arm (the video of this is included below).

After removing the sensor, I saw, under the sensor and on my arm, was a decent amount of dried blood. On July 10, 2020, I called the manufacturer, told them about the inaccurate readings and itching and burning around the application site, I was told that the sensor might have been faulty, and I might be allergic to the latex glue they use. I’ve known for years, that I am allergic to latex, but I didn’t know the product contained latex. It doesn’t have a latex warning on the box, and it’s not listed on the website either.

Online, I found that a lot of people are having skin irritations from the sensor’s adhesive too. The company would not reveal what the needle was made of when I called them.

The system is also expensive. My co-pay was $64.99 and the two sensors cost me $59.97, out of my own pocket. My insurance didn’t cover the cost of the meter, or the sensors. Each sensor only lasts fourteen days, so you have to buy a new set every two weeks, so it’s three pennies under $60 a month, for just the sensors.

In conclusion, a CGM is not a good, or even a viable option for me, and for many people who are sensitive to the adhesive, but, there are lots of people who love their CGM and swear by it.

I created the short video below, if you’d rather hear the details instead of reading them, and to show you how to apply the sensor, how red my arm looked right after the initial application and before removing it, how my husband removed the sensor, what the needle looks like, and how much blood was under the sensor and on my arm after he removed the sensor.

If you have any questions, comments or would like to share your experience with CGM, please write to me below.


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