[Subby]

Originally Posted by fairyblood

You can drive yourself batty worrying about whether you are 95 or 85. I personally am more then happy with either number.

As a type one there are so many factors out of my control that I just take my number do what I need to do and move on.

Jeremy, I think you'll find that's the kind of utilitarian approach taken up by many or most type 1s. This apparent need for "pin point accuracy" is simply a pipe dream if it doesn't exist, we have enough to worry about and to get on with what with managing the condition and having a life, so why sweat it if you've got "pretty good"? You do what you can with what you have. Certainly Type 1s can gain great control despite meter inaccuracy. And I'll wager that those of us who do have more difficulty with control, there are much bigger factors, some potentially alien to some type 2s, that may well dwarf meter inaccuracy as a control issue.

That said, I do what I can to keep an eye on my tester over time. Test against lab results. I will take a few tests if I suspect a number is wrong. I have another relatively accurate meter I will use to compare if I am really suspicious. If a meter gives me a lot of inaccurate results, it gets turfed, simple.

If and when affordable testers are significantly more accurate, I will celebrate. I think it will make our life easier and improve insulin therapy a little. Til then, as I said, you do with what you've got.

[notme]

Originally Posted by Subby

Jeremy, I think you'll find that's the kind of utilitarian approach taken up by many or most type 1s. This apparent need for "pin point accuracy" is simply a pipe dream if it doesn't exist, we have enough to worry about and to get on with what with managing the condition and having a life, so why sweat it if you've got "pretty good"? You do what you can with what you have. Certainly Type 1s can gain great control despite meter inaccuracy. And I'll wager that those of us who do have more difficulty with control, there are much bigger factors, some potentially alien to some type 2s, that may well dwarf meter inaccuracy as a control issue.

That said, I do what I can to keep an eye on my tester over time. Test against lab results. I will take a few tests if I suspect a number is wrong. I have another relatively accurate meter I will use to compare if I am really suspicious. If a meter gives me a lot of inaccurate results, it gets turfed, simple.

If and when affordable testers are significantly more accurate, I will celebrate. I think it will make our life easier and improve insulin therapy a little. Til then, as I said, you do with what you've got.

Couldn't agree more. I use the One Touch that goes with my Medtronic pump. I have tested it against lab work and it appears to be well within acceptable limits for me. My last fasting blood test said I was 109 and my meter gave me a 104 before the test. Good enough for me!

[jps]

Originally Posted by fgummett

I have also noted a variation in batches of test strips... one bottle may tend to read higher or lower than the previous.

There are certain tests in my lab that are notorious for this, it just depends on the nature of the test. My glucose reagent, for example, shows absolutely no variation from lot to lot (batches). Same can be said for about 90% of my reagents. However, there are some that show some lot to lot variability and it drives me absolutely crazy. For example, Vitamin B12 and Folate. I can have a two month supply of Lot "A" and my low control (we run three levels) will yield a mean of 150 with a Standard Deviation of 5 giving us a valid range of 140-160. Then we run out of that lot and go to Lot "B". After a couple weeks of testing, the mean will be revealed as 165 with a Standard Deviation of 8 giving us a new valid range of 149-181. So what that's basically telling me is if we run a B12 on Patient A on the last batch of Lot A and his value is 200, when the doctor orders another B12 on him in 3 days, he can have virtually the same exact levels of B12 in his system, and we will be reporting out a 220. Still well within the limits of laboratory standards, but I despise it. I want less than 5% variability on my tests.

Sorry for the long winded post. But essentially, yes, THERE CAN be variability from lot to lot with your glucose strips. DO NOT be surprised (or panic) if you see a slight "shift" in your values when you switch lots. You may not see it at all - again, its dependent upon the manufacturer and their standards for the test. Overall, they should still be relatively accurate though.

There's no question that manufacturers can minimize this variability and they can certainly increase the precision and accuracy, but that would involve improvement in research and development and much tighter quality control on their end.

What does that mean? A much higher cost to the end user.

[fgummett]

I noticed the test strip batch/lot variability some time ago but just this week noticed that the back of the test strip bottle actually support this as well...

I have 2 bottles of Contour test strips: lot 8MC3B03 shows 6.0-8.3mmol/l as acceptable control solution values, while lot 8HC3C02 lists the range as 5.9-8.2mmol/l

It doesn't phase me anymore... I just note it and move on. If I am extra keen, I will test with the last strip from the old bottle and also with a strip from the new one, just as I switch over.

I did read somewhere about an accurate unit made in Scandinavia (?) for around $600, with test "strips" at around $5 a pop -- that had to be refrigerated before use -- and IIRC required several minutes for a test.

[Tribbles]

The Norwegian health authority get meters independently tested before issue and for three batches of strips quite often one batch will be noticeably different. That is under lab conditions.

[jcaboose]

I'm new to this whole thing, just diagnosed with Type 2 earlier this year. I went to an Endocrinologist today, as I didn't think I was getting much in the way of help or direction from my PCP. When the nurse took my initial info, she did an "instant read" test, and my glucose level was 123. I had never been given, or told to get, my own meter. At the end of my appointment (about 2 hours later), they gave me a Bayer Contour meter and showed me how to use it, and my reading was 95. They also gave me a prescription for 200 lancets and test strips, which I took to my regular CVS to get filled.

It just so happened that they were having some kind of Diabetes Awareness thing today, and there was a guy from Abbott Labs there, and we started talking while I was waiting in line. They were giving away their Freestyle meters, so he gave me a Freestyle Lite and showed me how to use it, and my reading was 125.

I came home and had dinner, waited an hour, and then tested with both meters. The Contour said 153, and the Freestyle said 121. That didn't seem to make a lot of sense, so I figured I must have screwed something up, so I went to do it again and make sure I did it right - I washed and dried my hands again, put test strips in and got both meters ready, and then used a new lancet on a different finger. I used the same drop off blood, and this time the Contour said 141 and the Freestyle said 125.

I realize there's going to be some variance, but can I believe either of these monitors? Which one? The Freestyle seems to be more "consistent," but is it just wrong all the time by about the same amount? Is the Contour just a piece of junk and as reliable as throwing darts at random numbers? Is there another meter/system I should ask for instead?

I don't want to be freaking out if my numbers are jumping all over the place or reading higher than they really are, nor do I want to think "oh look, my numbers are normal, I don't have to worry about this any more" when my glucose is actually too high.

Sorry to prattle on, but any advice on meters and monitoring gratefully accepted.

Just tested again - Contour 187, Freestyle 151. Oy vey.

[Grunch]

There's something I don't understand.

My strips say this on the bottom:

cont L: 39-68
cont N: 89-121
cont H: 224-292

I understand those are measured on some kind of control solution but what do the numbers mean? Is it that the strips might measure anything from 39-68 on the same drop of blood? That can't be correct...

[fgummett]

Originally Posted by Grunch

There's something I don't understand.

My strips say this on the bottom:

cont L: 39-68
cont N: 89-121
cont H: 224-292

I understand those are measured on some kind of control solution but what do the numbers mean? Is it that the strips might measure anything from 39-68 on the same drop of blood? That can't be correct...

Perhaps there are three different control solutions: one to simulate Low BG, another for Normal and a third for High. In that case the manufacturers acceptable values for the normal control solution would range from 89-121..?

[jcaboose]

First thing in the morning, no food for 8+ hours:
Contour 191, Freestyle 150. These two monitors are well over 20% apart.

Confused and frustrated.

[NewdestinyX]

Originally Posted by Grunch

There's something I don't understand.

My strips say this on the bottom:

cont L: 39-68
cont N: 89-121
cont H: 224-292

I understand those are measured on some kind of control solution but what do the numbers mean? Is it that the strips might measure anything from 39-68 on the same drop of blood? That can't be correct...

Originally Posted by fgummett

Perhaps there are three different control solutions: one to simulate Low BG, another for Normal and a third for High. In that case the manufacturers acceptable values for the normal control solution would range from 89-121..?

Only one solution is made per a chat with my company. It's supposed to test in the 'nominal or normal' (N) range. If the solution brings you a number in the 'H' or 'L' ranges - the strips are bad. (But the meter could be bad which is weird too).

[Subby]

Originally Posted by jcaboose

First thing in the morning, no food for 8+ hours:
Contour 191, Freestyle 150. These two monitors are well over 20% apart.

Confused and frustrated.

Unfortunately it doesn't work that way, they could both have been within the 20% error range.

191 could have been top of a range approx 155 - 191

150 could have been bottom of a range approx 150 - 180

I say approximately, because causally working out the exact percentiles involved with a theoretical "accurate number" is not really useful, nor do I have the maths acrobatics to do it easily. These are rough illustrations.

That said, I really understand your frustration. I'd suggest testing both meters, multiple times, against lab results - soon if possible. It's worth remembering and doing the sums sometimes to illustrate for yourself - the higher the BG, the bigger the actual territory of error. With lower Bg readings, where I would suggest there is a lot more importance for some accuracy, the 20% gets narrower and narrower. That's something at least.

In the short term, if you notice a big discrepancy between meters or tests results at the same time, I suggest rewashing hands and taking another test to allow for another point of reference.

[fgummett]

Originally Posted by NewdestinyX

Only one solution is made per a chat with my company. It's supposed to test in the 'nominal or normal' (N) range. If the solution brings you a number in the 'H' or 'L' ranges - the strips are bad. (But the meter could be bad which is weird too).

So what about numbers between the low end of the Normal range and the top end of the Low range??

[NewdestinyX]

Originally Posted by fgummett

So what about numbers between the low end of the Normal range and the top end of the Low range??

I guess I'd be suspect and ask the company to send me a replacement bottle... I guess...

[fgummett]

Or... perhaps YOUR company only makes one test solution and OTHER companies might make Low, Normal and High control solutions

[NewdestinyX]

Originally Posted by fgummett

Or... perhaps YOUR company only makes one test solution and OTHER companies might make Low, Normal and High control solutions

Maybe.. would be weird if that were the case since my company lists 3 ranges on the bottle too yet only makes one solution. All you need to determine bad strips is a number 'out' of the N range. That part seems simple to me.