There have been several discussions here about whether seniors using Dexcom can get test strip coverage. @Terry4 managed to get Contour Next strips from CVS a while back but everything I learned while researching this blogpost would say that he was lucky and it is doubtful that CVS will continue to get Medicare reimbursement for similar purchases. The most recent Medicare policy article says that yes, you can get test strips but they must be part of a bundle from your CGM supplier. Unbundled supplies will be denied. Once again I am referring to Basic Medicare and not Advantage Plans, TRICARE, and retirement plans. Also just to Dexcom and not Medtronic. Medicare, Dexcom, and Test Strips 2022 | Test Guess and Go
5 Likes
I think it had to do with Dexcom getting approval. Saves money for Medicare if they don’t have to pay for test strips when you have a Dexcom. Dexcom then decided that it would be cheaper for themselves to not supply test strips bundled either anymore and to show a better profit line when getting other people to handle distribution.
But it’s haywire, even Dexcom tells you when in doubt get your meter out, but then you don’t need to test ? Mine has been off by 60-80 points with a brand new sensor a few times…once I took a correction for a 185 when I woke up, then realized new sensor, checked with my meter and I was a nice 105. I then had to get up and eat to cover it. Usually a brand new sensor reads a lot lower for me and is erratic the first 24 hours plus, so you are just supposed to dose blindly ? So it’s nuts…
That would be one of the biggest reasons Dexcom needs competition. They might care some now in regards to the Libre, because they will potentially lose a lot of the type 2 business to them because it’s cheaper. And it looks like they are trialing a cheaper version of a Dexcom, DexcomOne for that reason in other countries. But they need a calibrated more accurate sensor competitor and I worry that might not happen as the push might be to get the huge type 2 market now.
1 Like
My endo told me that the Dexcom is more accurate than the One Touch meter, and I shouldn’t bother to calibrate. I’m not inclined to believe him on this. At very least, the meter isn’t 20 minutes behind.
3 Likes
As with almost everything about diabetes if a doctor doesn’t have personal experience using a product their opinion can’t be blindly trusted. Too often they trust what they’re told confirming it in practice.
I like my endo a lot but they don’t know how to use a pump,don’t know how to use a CGM, and have absolutely no experience with the problems that they have or with troubleshooting them.
A 20 minute lag is not a big problem but when you have steady blood glucose and a CGM tells you that it’s level is 50 mg per deciliter off from what it actually is, it can’t be trusted until it is recalibrated.
New bgms are now required to be accurate more accurate than cgms are for FDA approval.
2 Likes
Where is this 20 min lag come from. Dexcom has a 5 min lag. That’s the lag for interstitial tissue in general, but there is also a lag in finger sticks in capillary blood it’s just not 5 min but more like 2 min.
And yes if you read the data, dexcom is more accurate than finger sticks as compared to laboratory instruments using the glucose hexonase method. 7.1MARD compared to average of 7.5 for fingersticks, and yes some score under 6 Mard but there is no clinical difference between a 6-7. A MARD of 3 or less is considered dead on accurate. No at home meters can do that only lab equipment
That is if it’s working right, and as we all know sometimes the sensors crap out at which time we need a back up just to prove to ourselves we aren’t crazy.
That being said my one touch meter is generally very close to my dexcom readings. Within 10 mg/dl in most cases.
I don’t recall where I got that 20 minute figure, but it’s within the 5 - 25 minute range that one study (sorry, no citation) I just skimmed reported. It has seemed reasonable, in my several years of experience.
This is an interesting study comparing blood draw lab test vs CGM during OGTTs.
Time-Lag Between CGM and OGTT
Figure 2 shows the distribution of possible time-lags (0, 5, 10 or 15 min) of the corresponding CGM measurement for each of the post-challenge OGTT glucose values. For the OGTT value at 30 min, there was a 15 min lag-time in CGM measurements for more than 60% of the participants. For the OGTT values at 60 and 120 min, the best match of CGM measurements was at the same time as the OGTT measurements for approximately half of the participants, but in 33% and 26% of the participants, a 15 min lag-time in CGM measurements at 60 and 120 min, respectively, was present.
FIGURE 2 Distribution of possible time-lags (0, 5, 10 or 15 min) of the corresponding CGM measurement for each of the post-challenge OGTT glucose values.
https://www.frontiersin.org/articles/10.3389/fendo.2021.753810/full
1 Like
through empiric evidence, I know that for me there is a constant 15 to 20 minute lag between what my blood glucose is and what the CGM shows. I often use that as a way to validate the accuracy of the CGM when there is a difference between my meter and the CGM. I check both of them 20 minutes later, especially if my blood glucose levels are stable, and if they are still not within a satisfactory range, then I calibrate the CGM. That keeps the discrepencies to a minimum especially as my glucose levels can be extremely volatile. The faster I can respond to them, the better I manage my glucose levels (and remember even fast acting insulin like novalog isn’t instant - it too have a 15 to 30 minute lag/reaction time before your body responds).
1 Like
Mine is a clear 5 min and also the dexcom algorithm corrects for it and if you ever watched carefully, sometimes it changes the values. That’s because it was estimating where you will be in 5 min and then uses the real numbers when it records the data.
If I was having a 20 min lag with a cgm it would be useless to me. My sugars change so fast. I’ve tested it. I eat 20 grams of carb test, My finger stick and dexcom respond nearly at the same time because the dexcom is programmed to anticipate your glucose. It’s not dead on accurate but neither is your finger stick meter.
If it was 20 min I could be at 200 and not know it.
If I was responding that way, I would just go back to finger stick testing.
Now unless you are talking about how long food takes to hit your blood stream, that’s a more reasonable time, because it takes that long for me too. But that’s not what I think we were discussing. The lag between blood and interstitial fluid glucose
2 Likes