I am not a diabetic, but he asked this on facebook:
This is for the scientists/lab rats out there. My mom got a new glucose meter, which came with a control sample with which to check the meter's calibration. The range for the control is supposed to be 95-135mcg/dl. Does anyone besides me think that it's an awful big range for a control sample?
What do I tell him. I think he and his Mother should join here at tudiabetes
I dunno, I never used control solution ever. Even on the "blotter" meters in the 80s...
Your friend is right. This is terrible. We have been let down by those that should be advocating on our behalf. Meters should be more accurate.
But that being said, the control solution is to check if the meter has totally failed, not to calibrate. I can't remember the last time I used the control solution. If I get a weird test, I repeat it with more controlled conditions and it again it is weird, I try with another meter and a different test strip batch. If that all suggests the meters is whacked, what is the point of the control solution.
ps. Besides, the control solution is "bad" within three months. If anyone has actually replaced their expired solution, I'd like them to raise their hand.
pps. I think control solution is a "deception" aimed at making you think the meter is actually accurate because it can be calibrated (when it actually cannot be calibrated).
At $1 per strip the function of control solution is to raise our costs by $1 per vial :-)
Unfortunately, a control range like that is pretty typical, as used in a medical laboratory to check that all the equipment is functioning. I used to work in a hospital lab for many years. Like bsc says, not for calibrating.
Actually, there is one use for control solution. You can drink it to treat a mild low. But it does turn your tongue blue.
I never use the control solution, it probably has a very persise amount of sugar in it but or meters are random number generators...any single test can be off...but the average results we can live with according to the manufacturers...and the FDA puts a stamp of approval on them.
...If something looks wacko I will try a different meter, someone gives me a meter every year and they come with a few test strips. (usually about 10)
The effectiveness of a bg meter is currently defined by the Clarke Error Grid. The Clarke Error Grid, for the most part, is there to make sure that a low tests as a low, a high tests as a high, and something in the middle tests as something in the middle. It has a tightest requirement for accuracy in the "middle" region (that's where the control solution is supposed to be) and allows meters to be more off it the number is really low or really high, but only as long as a high still tests as a high and a low still tests as a low. What that control solution does, is make sure that a number in the middle (the control solution is probably manufactured with tolerances such that it ends up in the range 110 to 120) shows up no more than +/- 20% off.
In the grid below, this 20% tolerance applies in region A, which is where the control solution is supposed to be.
Some might view this as a very loose definition of accuracy, but having lived as a diabetic both before and after home bg tests coming along, I can assure you: what's really important is that 200 doesn't end up testing as 35, or 35 doesn't end up testing as 350.
A link to the Clarke paper, Evaluating Clinical Accuracy of Systems for Self-Monitoring of Bloo...
Some typical home bg meter results on a clarke error grid, and some typical CGM results on a similar grid:
bsc...only you would know that...lol.
**GAK**
Next time I see someone with a blue tongue I'll know what happened.
bsc, you know this from personal experience....? you are the master of science experiments!
Count me as another who has never used control solution.