Meter Accuracy
 

Hi,

Here is a nice topic for discussion ;-)

Just curious to the various types of meters that everyone uses and their accuracy (in a comparison to a lab test). I currently have two meters; one touch ultra and a freestyle.

For my last lab tests (3 weeks ago), I brought the ultra with me. I found that the ultra (on THAT day) was 2 mg/dl less than my lab fasting BGL. Recently, I bought a freestyle meter and I generally like it more than the ultra, however, it reads 7-12 mg/dl LESS than the ultra. According to TheraSense (the manufacture of the freestyle), their meter's reading are correct and the ultra's are wrong (of course) because they analyze the entire droplet of blood.

Another thing that is puzzling me is that my last A1C was 5.5 (which equates to around a 115 average BGL). Now, I shouldn't complain or anything, but according to my ultra, my fasting BGL in the morning averages around 98 and my BGL 2 hours after eating averages around 104. I also test before I eat (lunch and dinner) and go to bed and my averages there are around 92. So, then what am I missing here - how could my A1C be 5.5 (non-diabetic range is defined as < 6.0) ? Am I spiking at night (while sleeping) ?

Thanks,

Adam

I am very curious to the answer to this question. I have (2) Freestyles and sometimes compare readings. They are quite close, so I guess they are reliable within each other. When I tested before my Dr's appointment, I was 16 pts higher on the Freestyle than the lab results. (I can't believe BG would drop from 76 to 60 in a 30 minute car ride.)

As for the A1c, I am guessing that even if you test 10 times a day, you still aren't seeing the entire picture of your BG. Who know what it is doing while we are sleeping, eating, exercising, etc.

Also, I have heard that if you send the blood to 3 different labs, you will get 3 different readings. So, even if the meters are a little off....they are consistant with the lab.

Hope someone comes in and tells us the scoop on this matter!

Hi Sherrielee,

When I spoke with the people at TheraSense they said that the freestyle meters generally run around 5-10mg/dl HIGHER than other meters and Lab Tests. They are really puzzled on why the ultra's results are ALWAYS higher for me (in fact tonight before dinner the ultra gave me 95 and the freestyle gave me 82) .... I was very impressed with TheraSense's customer support and their help - in fact, they are sending me a duplicate meter just to verifiy my readings.

Why can't a magazine actually rate the meters - yes, I know that consumer reports did a rating, but I was not impressed with that article.

I just like the low readings from the freestyle ;-)

Thanks,

Adam

The difference is in whether you are testing whole blood or plasma levels for glucose. Most meeters test whole blood while most labs test plasma. The whole blood reading will generally be about 12% lower than the plasma reading, so to compare against the lab when it is testing plasma and you are testing whole blood, multiply your meeter reading (if you meeter tests whole blood) by 1.12. Divide by 1.12 to go from plasma to whole blood readings. Readings can also vary between labs and with the technique of the lab technician.
Venous blood versus capillary blood also makes a subtle difference as well as whether the sample is taken from the fingertip or another part of the body such as the forearm. Figertip samples are best when you suspect that your blood sugar is dropping rapidly as this will show up there first.
Blood glucose meeters can be off by as much as 20%. The best thing is to use one meeter because that will at least give you the consistent trend for that meeter. The whole idea behind blood glucose meeters isn't to give you an absolutely accurate measurement, but to help you spot trends and determine if your blood sugar is rising or falling quickly.
The lab readings are usually far more accurate so if, after adjusting for the difference between whole blood and plasma readings, your meeter is close to what the lab readings are, you've got a pretty accurate one.

As for the A1C differing from your fasting and 2 hour readings, what your testing isn't showing is how high your blood sugar is going after you eat...it's showing how close to normal it is 2 hours later and when you haven't eaten for several hours, not what it does all those times in between. Given all that, I'd say that an A1C of 5.5 shows that you are doing pretty well! :)

Hi Lisa,

Well both the ultra and freestyle report the BGL in plasma levels (as do almost all meters these days) - that I am sure about. In addition, both meters advertise that they are accurate within 96.x %, so one of these meters is not telling the truth ;-) All I care about with these meters is accuracy/consistency and that is it -


Thanks,

Adam

Adam...the thing is that by industry standards a meeter can be off by as much as 20% and still be acceptable! Manufacturers can claim all the accuracy they like, but usually the "testing" that showed that is funded by the manufacturer themselves.
If you find one that exactly matches the lab results, let me know because I'll probably be out looking for it soon after! :)
I currently use an AccuCheck Advantage and it seems to give me readings that are fairly close to what the lab results show, if not a bit on the high side. If I had to choose, I'd rather that my meeter register high than low since hypos are only very rarely a problem for me.

For personal meters purchased within approximately the past three years, this correction factor from whole blood to plasma is already built in. The meter makes the correction automatically as part of its programming.

However, if you have an older meter (like my Glucometer Elite from 1997), then the meter's value should be multiplied by 1.12.

Hummm My insurance company will pay 100% of my strips if I use a Precision meter and strips. Anyone ever heard of it?

If none of them are accurate anyway, I'de rather save my $$ for ALA.

Never heard of it.

Whenever I go for blood work, I take my Freestyle with me and take a reading within 1 minute of the doctor drawing blood. The last time I got 96 (8:30 AM) and the lab results came back with 97. Close enough.

I'm a little bummed by the above report on the One Touch Ultra, since my insurance company will pay 100% of the cost of test strips for it but will pay nothing for Freestyle test strips. To eliminate this expense I was about to go out and buy an Ultra meter but I may reconsider now.

Any other meters out there which we know to be accurate? Therasense seems to be blacklisted by insurance companies. Nobody covers test strips for them, but always pays a significant portion for something else.

My insurnce company will pay 1/3 on the Freestyle strips. I think they are the most expensive ones plus the my pharmacist said that companies work out "deals" with certain manufacturers. To be honest, I looked up the Precision and it doesn't look half bad. (It is made by Braun, a name I have some confidence in.)

http://www.glucerna-precision.com/s...?page=221&cat=0

Edited to add: Jim, your A1c is so good, you should use the meter your insurance pays for and just take it in to your Dr like you did your Freestyle. Save the extra $$ for ALA. I am thinking that I will be spending a lot of money on strips if I hang on to that Freestyle.

Also, having looked at this link...the Precision meter and strips are definately the most expensive I have seen. This meter looks great!

Hi,

Well it looks like something was wrong with my NEW freestyle meter. I brought it with me to the Diabetes Center and they have some lab equipment (sorry can't remember the name of the machine) there that is used to calibrate BG meters. The freestyle was giving readings over 20% lower than the lab equipment. In addition, my CDE said that this was the third freestyle meter this week that has had issues. I returned the meter to Walgreen's yesterday ;-(

Thanks,

Adam

Hi,

By the way, I forgot to mention that I did receive the freestyle replacement monitor that was promised to me by TheraSense and guess what --- that one was also off by around 20% ;-( I am trying to get a hold of the TheraSense rep here in Atlanta so I can turn the monitor back over to them. I guess that I will stick with my ultra ;-)

Thanks,

Adam

Freestyle Strips Covered by Insurance After All
 

I called my prescription drug carrier again and this time the phone clone actually took the trouble to consult the pharmacist. It seems that my Freestyle strips are covered after all by the plan. $20.00 copay for a 90 day supply if the doctor specifies that particular kind. They've got a deal.

I'm about to go for another A1c. Will do the comparison check and let you know.

Freestyle's been great for me. Wonder why yours is such a bummer.

BTW, I checked out the Glucerna Precision Soft-Tact system, which looks terrific. However, the strips don't seem to be covered and the meter's over $200.00. Maybe when my ship comes in....

Hi switzr--

Just to give you another data-point, I am using the Ultra and carried it in with me for my first lab test...it came in within 1% of the lab result (meter said 110/lab said 109). Considering that the techs tell me the lab claims a 4% margin of error, I consider the Ultra as "dead-on".

I should note that this is my second Ultra meter...the first on started out fine, but became increasingly erratic after 6 weeks of use. At the end, I was getting readings differing by nearly 80 mg/dL from two sticks in the same finger done 2 minutes apart! The replacement (provided free) has *never* shown a variance of more than 2 mg/dL under the same conditions.

I have 2 Freestyles. They can vary from 2 to 20 mg/dl from one moment to the next. In the brochure, it says if you do more than one reading and they are different...go with the highest one. What does that tell ya?

I am planning on get my FREE precision and FREE strips when I visit my Endo in October for a prescription. Maybe I am not even doing as good as I thought. <sigh>