Continuous Glucose Monitoring (CGM) Tips

It is widely agreed that blood sugar regulation in people with diabetes will lower the risk of microvascular complications. When you dip too low without warning,  control can be hazardous. By offering us a layer of protection with automated alerts when blood sugar is too high or too low, CGMs (Continuous Glucose Monitors) make monitoring more feasible.

Don’t calibrate when…

A significant rule of your system calibration is to ensure that you never calibrate when your blood sugar increases. Perhaps you injected some fast-acting insulin an hour ago, for instance, and now it’s time to calibrate your CMG. Your blood glucose could fly down the slope, and you could only crest the hill with interstitial glucose. You will only confuse your CGM if you enter your fingerstick blood glucose number at this stage.

You want to make sure that the horizontal arrow/flat line is just calibrated. Take it a step further: make sure your blood sugar does not change from food, sudden changes in temperature, recent fast-acting insulin, or workout. Also, make sure that nothing can quickly affect the blood sugar in the next 15-20 minutes (i.e., before or after eating or showering).

You will want to make sure you give it precise readings when you calibrate your unit. It is important that you have a concise description of the fingerstick. As they say, “garbage in, garbage out.” Make sure to obey all the rules shown in “Other Calibration Suggestions” of this article for getting good fingerstick readings.


Review the highest accuracy for these

1-Proper hydration is crucial to the device’s success. Your body will automatically draw water from your interstitial fluid into the cells if you are dehydrated. That keeps the sensor high and dry,

2-Rapid changes in the temperature of your skin can also influence your sensor’s results. Users sometimes (but not all) see “shower spikes” where, due to the effect of hot water on the skin and interstitial fluid movement, the CGM reading goes up rapidly. You want to ensure that you do not calibrate your CGM 20 minutes before or after a shower or other drastic temperature changes, in compliance with the guidelines we set above.


Consider this

If you calibrate and inform the CGM that your blood glucose is 100 mg/dL right before you hop into a shower, your CGM knows that it lags about 20 minutes behind your actual blood glucose (fingerstick). If you get in a shower and you get a “Shower Spike,” you’ve just got your CGM confused. Please think of the roller coaster analogy; when you’re calibrating, you want it to be steady for 20 minutes at both ends. If you manage to do this, the system works surprisingly well!

Compressive lows are another problem. When there is a strain on the sensor site, compression drops occur. This has the effect of the detector moving the interstitial fluid away. By doing so, you’re going to get a fake low reading. This can be a frustrating calibration cycle. The false low that occurs when you sleep on your sensor is a typical example. You can receive low alarms of 50mg/dL from your CGM, but your fingerstick reads a chilly 90mg/dL. Avoid the temptation by calibrating it to read 90mg/dL to correct it. This will hurt future precision since the glucose concentration is currently low at the compression site, and it requires several minutes of decompression to re-equilibrate it. Do not be afraid to try a new sensor position, particularly one you may not sleep on if you’re having trouble getting good results. With sensors on the calves, behind their triceps, and back (small back or under the pant line, but above the actual buttock), people seem to be reporting good luck.


Other Calibration Suggestions


1) Have your hands washed and dried.

2) Have a strong enough flow that the blood doesn’t need to be squeezed out.

3) Consider the second drop is used. Only brush out the first drop of blood that comes out and use the 2nd one instead to do this. The 2nd decrease would more closely reflect the circulating blood glucose.

4) Do a second one before using the reading as your calibration number if the fingerstick reading does not meet your standards.

5) Ensure that you purchase the most reliable meter you can!

Leave a Reply

Your email address will not be published. Required fields are marked *