Meter question- vastly different readings

Genuinely curious on this.

My insurance no longer covers the freestyle strips that go with my omnipod. So I’ve been switched to accu-check guide me. I changed out my dex this morning and it’s reading lower than both meters so i was thinking of calibrating

Question would be this. Dex said 90 and omnipod/freestyle said 115. Accuchek said 137 and then 140. I just left the dex alone and have not calibrated it.

I keep having that 20-30 point difference per meter and I’m not sure if that’s bad. I had a low last night where omnipod showed low 50s and the accuchek showed mid 60s. For me at least, I would treat the 50 much more aggressively than the 60s. I know I’m probably just going to drive myself nutty by comparing, but the low thing actually has me a bit on edge about whether or not I can trust the value of either meter. I mean I can just go off how I feel and treat appropriately but still hard because 15 g at 65 is going to shoot me up more than likely and 15 g at 50 might not be quite enough

Any suggestions or any feedback on which meter is more accurate?

Hi @Tee25. One thing I would suggest - see if your insurance will cover your preferred strips with additional authorization. I’ve had a couple of my rxs fall off my plan’s preferred formulary, and while they may not cover them for new users, they might let me continue since I was already on board. My doctor has to provide some documentation - yours should know what to do. My pharmacist was the one who told me what I needed to do and yours might be able to do the same.
Dexcom is accurate to within 15%. That said, some people do find their first day or so on Dexcom can give “off” readings compared with fingersticks, so if you just started your Dexcom that could be why. Due to their function meters should be similar in accuracy so it’s surprising your Accuchek was so different. The only thing I can think is, perhaps some steps are affected by medications that may be in your system (I’m guessing here); or maybe something was on your fingers that affected the readings. Sorry I can’t be more help.

No thanks that’s helpful! I’m trying to go through the prior auth stage but even with doc documentation it’s been proving difficult to get coverage. Washed my hands before and dried so don’t think that’s it. It’s a new vial of the accucheck though so maybe I’ll try a new vial and see if I get different results

Taylor @Tee25 , I can appreciate, and understand, the frustration you are experiencing. Statistically, and by MARD lab testing, your Dexcom device - G6 and G5 - is considerably more accurate than any fingerstick meter. that is, if your Dex sensor is inserted properly and has warmed up - during the first 12 - 24 hours the Dexcom MAY lack accuracy. The BIG question here, is how did you feel? If you felt low, 50s or 60s, be safe and eat something; and risk going higher than you might like.

What you didn’t tell us is more important than the numbers you provided. In what direction was you Dexcom arrow pointing, and what were the 3 or 4 previous readings? Remember that there can be a 10 to 20 mg difference between BODY glucose level and BLOOD glucose level; an arrow straight down indicates you are dropping 2 to 3 mg/dl/min - 2 down arrows down means 3++ drop in mg/dl/min. Meaning, that Dexcon reading of 100 with a single down arrow and a meter reading at the same time between 70 and 85 are both accurate.

Keep in mind, that the Dexcom instruction, and the FDA G6 approval letter, say that the arrow and previous sensor readings must be used for insulin dosing calculations.

I’m not on a pump as yet, but don’t understand the comment “the freestyle strips that go with my Omnipod.” I know Omnipod is a pump for insulin, but how do the strips figure in?

Ref the readings, I’m not an expert, and there are people here that can explain it far better, but I understand meters vary significantly; FDA requirement I believe states 99% or readings must be within 20% of lab test, 95% within 15%, so if the Dexcom is high and the meter low or vice versa, that can be quite a difference. Similarly for the different meters. Every time I see something like this, I’m reminded of the old saying: “A man with one watch ‘knows’ what time it is, a man with two watches is never sure.” Not real helpful is answering your question, but a good philosophical approach.

You’ll find people here, on T1Exchange, FUD, and other sites that strongly favor calibration as well those that avoid it at all costs. So, its a personal decision of what seems to work best for you based on experience. I personally will calibrate, but understand the best time is when your BG is steady according to the Dexcom. I tend to meter test if Dex shows low, but I don’t feel it, or if Dex shows high, and always if the Dex has been erratic, jumping around. Probably not the response you wanted, just my short experience over the last year.

Thanks for any response on the strip question I led in with!

Hi @Tlholz

The omnipod system is an insulin pump you fill with insulin and glue to yourself. Omnipod has No buttons. No display. You use this system through this smartphone-like device (no it’s not a phone, it’s a dedicated piece of hardware for the pod) called a PDM. This PDM has your stored programmed basal rates and other user data. This PDM has a built in blood sugar meter, and it’ happens to be a FreeStyle. So if your insurance isn’t cooperating, you need the pod, the pdm, and a separate blood sugar meter. Hope this helps!

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I agree with the previous advice .I almost always end up over treating a low bg. As long as you don’t get crazy a little high is a much safer platform than any low. Low bg are very different person to person, I have a coworker who passes out at roughly 55, I have actually checked and treated myself down into the 30s a couple times in my 24 yr experience. I can safely say that low bg is not a good thing but treatment is also very different person to person. My coworker keeps the gel tubes on hand and I keep the tablets. He will see a sharp short term spike from a tube but return to normal pretty rapidly all things considered. I am much slower to react but once I go up I tend to stay up for a while. That being said I make much better decisions at 150 than 50 so I typically over treat. Good luck with your insurance company, maybe you can get a waiver to return back to the system you know and trust.

Just my experience, but: I wear Freestyle Libre (only sensor supported by my insurance). The sensors are almost always off or pretty off - but I believe my body is at least partly to blame. Ever since I caught on to this, I always test with both sensor and one or both meter(s) (Freestyle Light and Contour Next). The meters always agree. The sensor can be way off, might be higher than the others at in the first 24 hours or so, but always is lower than the others within 3-5 days, and if I leave it on (because insurance won’t pay for extra) it’ll usually be testing at about 40-64 on the 14th day regardless of my actually bloodsugar. The farthest off I ever saw it, a sensor said 64 and my BG was over 200. I mean, DREADFULLY off. Rarely, I get a sensor that might be sort of somewhat close to normal for the duration, but that’s not as common.

The sensor, though, gives me what the meters don’t: a knowledge of whether my BG is going up or down, and how fast. I find that invaluable.

However. Like my mother, I have a tendency to form excessive scar tissue. A lot of it. (Her appendectomy scar started at I think she said about 4" long when she was 10, and was a good 15" long by the time she died at 80 - and she claimed it was still growing.) Unlike her, I figured out that for me eating dairy and gluten was exacerbating it. I scar a lot less excessively now than I used to. But I think my body is still trying to gather plug up canulas at a stupidly fast pace. Mom was a lifelong dairy addict, and had trouble with all of her surgeries late in life because of crazy scarring (augh, the colostomy bag); I want to avoid that. It’s also not uncommon for my Omnipod pods to not last 3 days before it seems like I’m not getting all the insulin they’re trying to deliver, although I can’t figure out where the insulin would be going instead. I should draw out what insulin is left in such a pod, one of these days, to see how different the amount is from what the PDM said before I stopped it.

This current sensor is unusual even for me. Usually the first 24-36 hours, a sensor can read a little higher than the meters. This one was about 25% low from the outset. The meters agree with each other (I actually also have 2 old Freestyle meters that I thought I lost, so there are 4 meters), it’s clearly the sensor that is in the minority.

Anyway. Just a data point. My joints and tendons and at least one organ are all full of cysts and scar tissue, it’s not like canulas and syringes are the only problems.

So if you’re diagnosing a meter-sensor discrepancy, think outside the box.

Noz @theNoz I can hear your frustration with “diabetes technological advances” and, I detect a longing in your voice for a return to the good old methods. I may be over reacting.

What U did years back was maintain a “Pro & Con” tally sheet for a period of time and used this to set a path for treatment. I also decided that not all “advances” are need not be the right method for me. I read an interesting article earlier this year [[I’m looking to see if I saved it someplace] reporting on a survey of diabetologists that appeared to indicate that effective diabetes self-management has declined between 2020 and 2019; this survey was based on HbA1c results and not the more meaningful Time-In-Range. What the article DID NOT SAY was that the 10 year period in question coincided with a marked increase in use of technologies such as CGM and Pump.

Personally, I’ve had the fortune of my body not rejecting my current use of technology and am able to enjoy good management with almost complete “hands of” iAIDs.

Can you please provide the reference for this? This was not my understanding, nor has it been my experience (the latter of which doesn’t of course mean anything w/ respect to statistics, I know). Also, if this is so, why would CGMs need to be calibrated against a finger stick (rather than vice versa)?

Here’s a recent paper, e.g.: Seven-Year Clinical Surveillance Program Demonstrates Consistent MARD Accuracy Performance of a Blood Glucose Test Strip

On the other hand, info I found said CGM accuracy is around 9-14% (so lower accuracy, on average) For ex: Basics and use of continuous glucose monitoring (CGM) in diabetes therapy

Thanks all! I’ve carried on with experimenting and I have found that the omnipods built in freestyle meter reads lower on average for highs and lows, but if I’m in the 100-150 range my sugars are within 10 points on either meter which is really splitting hairs. Interesting enough, my contour next is usually in between the accu check and freestyle and I would say that it’s the one my cgm closely resembles the most.

Also thanks all who said to rely on symptoms and what I did. I did treat since I was feeling low and even if I hadn’t felt low, I still would’ve done some sugar since a reading of 70 or lower is considered low to me and I would want to treat!

Diabetes does wonders for our analytical skills, doesn’t it! Any progress on special authorization for your Freestyle strips?

No! CVS keeps rejecting it even with a prior authorization so not really sure what to do from here unfortunately