I’ve had a Freestyle Libre for over two years. Ever since the beginning, at least half of my sensors have given me readings twenty to thirty points or more lower than my ReliOn Micro glucometer. And lately they seemed to have gotten worse. I trust my ReliOn far more than the Freestyle, as I’ve taken it with me and compared it whenever I’ve had blood draws, and it has averaged reading only two percent higher than the blood draw result.
After much consideration I decided to switch to the Dexcom G6, and started the first one today. My first reading was 93. I thought “Good. That will allow me to have my beer before dinner,” as I expected I still had enough insulin left from lunch to cover it. But the number started dropping. 83. 57. 40. No symptoms. Okay, bring me some pretzels with the beer. The reading continued at 40 for over an hour. Then I decided to go ahead and eat dinner without pre-bolusing.
When I finished dinner and the Dexcom still read 40, I decided that it had surely had enough time to catch up with an actual blood reading, so I used my ReliOn to compare. Oops. 290. Then I realized that my last Freestyle sensor hadn’t quite expired yet. I hadn’t compared them up until then because I was thinking it expired an hour or two earlier. 261. Okay, so I injected 14 units of Humalog. My Dexcom is still giving me readings in the 40s and 50s, three hours after I cracked open that beer. The Freestyle sensor has expired. Insulin works so slow in me that I won’t bother to take another ReliOn reading for another two or three hours. Because of another medical problem I’ve had lately that has given me higher than normal readings, my guess is that I may have under-estimated the insulin I needed rather than over-estimated with that 14 units, so I doubt that waiting will present problems.
I’m obviously new to the Dexcom. I’d appreciate it if some of you who are experienced with it will give me some hints of what might be giving these crazy readings. Something I did wrong? I have a receiver only, no smart device to go with it.