Dexcom G5 arrow and treating lows

My daughter has T1D and uses the Dexcom G5. When she’s going low and the number is, for example 90 with arrows doubling down, I typically check with her meter to be sure. Today, the G5 was off by 40 points ( her actual BG was higher). Still, after calibrating, my Share showed her number doubling down. How does one know how much to correct without the number shooting up?

Dani @dsiizuka, when I’m in “that guessing game” with my meter and G5, I try to follow what for me is a safe route. First off, her G5 has a better “score” for accuracy, when compared against lab blood tests, than most meters - a meter can be considered accurate if it’s reading falls within 15%/15 mg/dl while the CGM is held to a higher rate of accuracy.

What I do, to be safe when I get double arrows down below 100 is suspend my pump and wait five minutes to see the next G5 reading. If it continues going down I will take about 12 grams of fast acting carb and wait.

Just this morning about 1 AM I was awakened when my recorder announced “falling” and my reading was 96. Without getting out of bed, I suspended my pump and waited for new readings; the next reading was 104 and five minutes later 114. I immediately went back to sleep. I guessed that the “falling, and 96” was caused by the way I was sleeping - sometimes called “a compression” false reading.

Bottom line - play it safe and try to avoid hypoglycemia which do more harm than correcting with carbohydrates so that your daughter’s BGL spends a little time at the upper reaches of “her in-range”.

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@dennis When you say that you “suspend my pump” is that the same as reducing the bolus? My daughter has only been on the G5 for about a month and I am still learning all the terminology and exactly how the cgm works in conjunction with the pump (she has the tslim). I have noticed that when she falls low or goes high I tend to panic and I want to correct her and I have to stop myself from giving her too much for a high or low and making her swing the other way. the correct part is easy, the wait part not so much. Always learning!

@dsiizuka Thank you for asking this, Dennis is always really knowledgeable and I find that other people tend to ask the questions I wonder about myself.

Hi Karmella @aakrzeminski, thanks for asking - I will always try to clarify my meaning of a post and the terms I use.

When I say “suspend”, that means to stop the pump from delivering all insulin, both bolus and basal. Absolutely no insulin being currently delivered.

There are two implications or conditions for which I use “reduce” - one for basal and the other for bolus.

  • Reduce BASAL by entering a “temporary basal rate” of less than 100% - when her pump is in normal mode it delivers at 100%. I select a number less than 100 based on my experience, my current BG reading and what I expect to be doing - for instance if my BG is in expected range and I’ll be bike-riding for three hours I might set my pump at 40% for four hours.
  • Reduce BOLUS means that I increase the denominator in my meal carbohydrate formula. For instance if I want less insulin with my 60 gram carb lunch I would divide the 60 grams with 16 instead of my usual 15 giving me 3.75 units (60/16) instead of the usual 4.0 units (60/15).

Keep in mind that “temporary basal” settings may also be used at times when BGL is running high such as sick days and during menstruation periods; at these times you would enter a number greater than 100.