I am finding I still test a LOT in spite of wearing a Dex. I thought it was supposed to cut down on that?

One of my purposes for getting Dex was to cut back on the number of times I test per day. I use way too many strips. However, because I don't trust my numbers on the Dex I find I still test just as much! I know that we must still test before eating, and are not to trust the Dex for calculating boluses. However, there apparently is a 20% margin of error on the Dex, and I find that too much especially when heading for a low. That could mean the difference of a serious problem or just the thought of "oh brother, I'd better eat something." So I get nervous and I test as much as I have always done. I am usually about 20% off in my readings. Occasionally I am pretty close, but not most of the time.

What are your experiences? I REALLY want to cut back on test strips.

Thanks :-)

While the Dexcom numbers aren't always spot on, the trends usually are all I need to make decisions, and I end up testing a few times a day just to make sure the two are still calibrated to each other. The most important part is to calibrate the Dexcom when you are level - and then don't calibrate it again unless it's trending off. I read it here all the time from people that try to calibrate when they aren't level, or still calibrate 5x+ a day, but in my experience it never lead to any more accuracy (in fact it was worse with frequent attempts to calibrate).

Keep in mind that the Dexcom uses interstitial fluid, so readings will always be ~15 minutes delayed. That's especially clear if your numbers are moving quickly.

Ah-- that could be part of my problem. I probably over-calibrate. Also, my numbers usually move very quickly in either direction; my endo remarks on that. I just LOOK at a carb and my BG shoots up :-) I think Dex just needs time to catch up. but of course I get panicky when it's on the way down. Thanks for the advice! I'll try resisting the urge to test and calibrate to let the thing settle down.

I've never really found that it cuts down on testing overall, but it does cut back on the "can that number be right, I should double check" testing that ended up using up a lot of extra strips each month... with the dex I have a much better idea of where I am in between fingersticks so I don't find myself needing to "double check" nearly as often.

I only do the two calibration testings that dex calls for.

I can tell the way my body behaves when I'm high and when I'm low so I use dex as a guide for that.

Same here. Still testing 8 times a day.

The Dex rep gave a talk to our pump group last month, and I asked him that question, and he said that it's OK to calibrate when your BGs are moving. And he said that the delay was more like 5 minutes. So now I wonder which one is the right answer, LOL!

I do test a bit less with the dexcom. If I feel fine, the number on the dexcom is fine, and there is no 'event' (carbs, exercise, whatever) I usually skip on the fingerstick.

Of course the reps will make it sound more appealing. While you certainly can calibrate as often as you want, experience shows that fewer calibrations is better. I see it time and time again here. The people who have been on dexcom for a few years have it down well and find they don't need to test more than 3-4x. Personally, I test 1-2x a day typically and my last a1c was 5.9. There are still days when I will test a lot, but that's when I'm active, sick, has rough highs, etc. - but typically only 1-2 is needed for accurate readings afterwards.

If you test twice within a minute of each other, are your numbers EVER the same? Mine are not. When calibrating a new sensor, we must enter TWO BG numbers. Mine are never the same.

What I am trying to get at is that even my OneTouch Ultra varies quite a bit -- just the other day I mentioned my numbers from the Ultra were about 30mg/dL different when I was doing an initial calibration. That's quite a swing, eh? Should I trust it?... (I have been for over 30 years now...)

So, my point is, NONE of these devices are 100% completely accurate: not the OneTouch; not the Dex. You also have to take into consideration how you feel, and factor that into the mix as well.

I am basically brand new to the Dexcom (since Oct '11), and I find I hardly ever finger prick now, except when a calibration is requested by the Dex. This is also great because I am generating less waste.

I know that some folks here recommend not to, but I bolus off the Dex numbers just fine, unless I am trending upward or downward. Then, I know it's time to run a manual test. Other than that, I am fine using this brand new device to guide me. I think it does an extraordinarily good job at what it does.

Good luck getting yourself aligned with your Dex. I think you may need to relax and trust it a bit to get settled in.


This excellent post for a few key reasons.

As I use insulin and also watching BG to catch it going sub 100 and hitting the liver emergency add when bg drops sub 70, the delayed averaged respons of the Dexcom can be pain in the derriere.

Another issue is the accuracy of finger prick readings on my body.

Not withstanding using alcohol swabs and fresh lancet on each caveman reading; I have found most reliably that it pays to take a readiing from my best finger on each hand. Many times the two readings are within +/- 10 points. Other times they can be 210 on one hand and 164 on the other. I then run another test on a different finger on the high reading hand and the new reading swings to within 10+/- 10 points of the lower hand. I average that and use as a BG entry for dex.

The clot morans who peddle this stuff and textbook instructions how one gets a perfect reading every time on the caveman machine completely ignore the physics and chemistry of the human body. The blood system is a highway/pipe that liver, kidneys all dump into along with lungs - oxygen , hormones etc.

The things added are done so in block and NOT perfectly sized - stoichimetrically sized, fixed packet size and mixed so that finger stick readings remain stable.

Munch on a glucose tablet and immediatly test with caveman machine and see how high ones BG soars to giving one miocardial infarction.

The blood system is more analgous to the ethernet where things are stuffed on willy nilley not like token ring whereby all packets are same size and perfectly lined up and timed.

If you have never seen a big liver do a liver dump adding glucose and watch BG soar to 511 -max and slide back down to 278-311 as heart averages/dilutes the glucose as it pumps around the body, you are missing an interesting show.

So, yes, 10 strips a day plus $ 300 plus per month on dexcom sensors.

At its best, assuming perfect readings every time doing one strip per reading; then one has 2 strips a day for calibration and 3 to 4 strips to dose insulin or more - 3 meals plus night time shot). That is 6 caveman strips a day strips assuming no caveman mis readings.

Lows are always the issue and thats why this farce discussion ove acceptability of +/- 20 % is a farce and unacceptable. High end - no sweat.

Once my readings get down to under 110, my body starts really moving the glucose and I can see it shoot lower fast and fly past 100 and be at 70 in a heart beat.

I am one of those tired and fed up with all the apologist clap trap and FDA inaction and rear end coverup excusing this.

My read is my most optimistic costs are running:

a) 31.00 a 50 strip barrel mail order at 10 strips a day is:

0.62 a strip x 10 = 6.20 a day x 30 = $ 186 per month

assuming one gets 12 days use per sensor and price of 310 for 4 sensors;

a single sensor is 77.50.

30 days will require 30 / 12 x 77.50 = 193.75 per month

* total combined best case costs would be $ 379.75

worst case costs assuming 7 days use per dexcom plus 10 sensors buying test strips at your local drug store at $ 77 a barrel would be:

strips 77/50 * 10 = $ 15.50 a day @ 30 days is $ 465 a day.

dexcom sensors = 30/7 * 77.50 = $333.25 per month of 30 days.

combined worst case costs - 7 days a sensor and $ 77 abarrel strips is $ 798.25

One can quickly get an idea of the punishing costs of diabetes and its care.

Bearing in mind this is a family orientated web site, I was told to watch my language.

That in mind costs like this tear people and families into the dirt with these crushing costs.

I am fed up with all the tax free associations that seem powerless to stop these outrageous costs. Politely put, I do not see any of them lifting a finget ( or in less polite words - doing jack crap over shinola) to get these costs under control. Maybe we need a punishing anti-trust action backed up with jail sentences to get somebody's attention.

On another front, I am delighted that President Obama has chosen his key agenda to give free birth control to a certain portion of our population.

Possible, the plight of diabetics could equally be addressed. Maybe California can stop taxing these supplies.

One lives in hope.

Thanks to all for responding. Much good advice here. I should know better than to completely trust sales reps and the product documentation stating it cuts way back on your testing! As "jims" stated, yep, my BG shoots down like a shot as soon as it gets to around 100. The Dex has been super-helpful for catching those trends, at least.

The alarm, even with buzz, doesn't wake me up all the time so I have to really do some interesting things to get it to stay right up against my skin while I sleep. If I put it next to me on the nightstand it loses signal when I turn over in my sleep, laying on the sensor. This doesnt' happen when I have it secured on my, um, unmentionables.

On a positive note, it HAS helped me keep better track of my BG most definitely. My A1C has been going down. I do not want to get rid of Dex by any stretch. I panic about being laid off- It really stinks that if someone loses their job or bad/no insurance, they can't afford new technology that in the long run will save them money and complications. (and possibly lengthen their life.) You should be able to buy as many strips as you need, and have the gadgets that prolong a healthy life. Straight shots do not work for me at all, as my BG is so very very touchy.

I can't imagine my Dex unit is all that different than yours. I can keep my receiver in my pants pocket several feet away from my bed and turn over as much as I want -- sometimes laying on top of my sensor (placed on my abdomen), sometimes not -- and mine doesn't miss a beat. You might want to follow up with Dex about this. I believe in the manual it says the sensor and the receiver should be within 5 feet to work properly, and surely you turning over at night does not place you more than 5 feet from it, right? I've been well over 5 feet from it and had it do a pretty good job of keeping track of my numbers.


Yes, my nightstand is right next to the bed. It picks up the signal most of the time, but if I'm laying on the sensor it tends to lose signal. You know, this got me thinking. I have one of those thick mattresses, and the current nightstand I have is about 6 inches lower than the top of my mattress. I wonder if somehow the bed/bedsprings are blocking the signal? I will try putting the receiver on top of something to make it even with my mattress and see. Now that I think about it, when I've been in hotels and put it on the nightstand which lays even with the top of mattress, it works fine. Usually I can even go to different parts of my house, sometimes more than 5 feet away, and it still works. It must be something about the bed.

The lady doth speak accurately.

I too keep my receiver in pants pocket but I have to ensure it is in pocket on same side of my body as dexcom tranmsitter/sensor on my arm or it will disconnect. Inside a metal shouded trailor, I see easily see 10 feet separation and not lose tranmitter. At home in a townhouse with units each side and checking for RF fields from 100Mhz to 3 gigahertx, I can see all sorts of other radiators that seem suggestive why my receiver disconnects from my tranmitter while it is in range and me sitting at dinner table and units within 2 feet always. In fact the worst perfomance on disconnects and interference has always been at home in my condo.

On another case, at my dentist where it has worked mostly; one day it disconnected and stayed there till I left and got back in my car and the two immediatly connected - no sweat. I have no idea who was running the diathermy machine, RF energy source or why.

Also, for some, rolling around can compress veins and arteries and cut off Dex readings.

Been there done that. Most annoying. Didn't even scrape tranmitter sensor off.

Due to fact that my BG can sometimes shift around faster than dexcom can track, I end up testing with caveman to see where we are. This has proven beneficial but expensive. A number of times for reasons unclear, I will see receiver showing diving readings, I grab glucose tablets and immediately run a caveman test and low and behold, Caveman stable at 150 or 164 both hands and all is quiet.

False alarm - dive alarm.

All that said, I still appreciate the Dexcom trend data and am able to compensate/cope/translate Dexcom readings.

Alll that said though, there should be on-going improvements in the technology moving forwards and nor is it a crime to question bizarre behaviour that depletes one's piggy bank buying caveman test strips. These test strips should be the lowest cost item purchased in ones care with Doctor's and meds being the larger share.

The issue of filtering plus interstialial delay can be as high as one/half hour or more and released specs provide no better clue than that.

A younger body in good shape on the circulation system could well see shorter delays that may be as good as 5 minutes. i do not as 64+ year old goat.

Michael, I've had the same issues Kate describes. When I started on Dex, there were many nights when I was laying on the sensor on my stomach when the receiver just showed out of range even though it was inches away. Since then I've changed how I sleep and don't put weight on the side with the sensor and never have a problem. Something about pushing on the sensor just didn't work out well.

As far as range, I've found that it generally doesn't go through me well. While cycling, I can leave the receiver in my jersey pockets (in the rear) on the same side as the sensor, and that works fine. If I put it in the opposite side pocket, it only catches maybe half of the readings. I find that I get about 10ft of range if it's open space though.

Do you have lots of springs in your body that might block the signal??? j/k :)

That's so odd that it behaves so differently on different people. I put mine in my lower leg pocket of my NEMA Telonix shorts (lower down on the side/back of my right leg), and it picks up fine, no matter which side of my tummy the bug is on. Makes ya wonder if it's you/me, or the Dex which causes the differences...


I have heard that the charge level seems to make a difference too. If you plug it in everyday, then it might have a better range. I tend to let it drain each time until it says the battery is low before charging again, so maybe that is affecting it - who knows!


Success of performance in my opinion depends upon how much background RF noise in the 400 Mhz band in your area. Secondly, I am told line of sight tramission path and any flesh in way blocks signal.

Thank you for sharing your data and helpful information.

have great day.

As Andy points out about charge level may affect.

As the type of battery technology being used , I believe it is best to cycle battery up and down from full to low charge to exercise the battery. Leaving it every day on charger may be conducive to the "memory " problem hitting the battery in a year flat. That is battery indicateds fully charged but when you go to use it, the battery is suddenly flat.

The only rechargeable battery that loves to work on a float configuration on the charger all time without getting memory problems is the lead acid battery but that is only used in cars ( not new hybrids) and other applications. All the rest are nicads and berillium style.

I found that by changing my site location, my readings became more accurate. I was about to throw 'Dexie' out the window, when someone suggested switching to a different location. I went from the abdomen/tummy area to my thigh. So often the reading is within 2 to ten points. However, sometimes it can vary more and as I never know when this is, I still average 8 BG tests/day. It is very useful for trends.