Bayer Elite XL vs. Therasense Freestyle Blood Glucose (BG) Side-by-Side Tests

Compared with vet's large lab meter and handheld meter

Subject: Punkin's feline diabetes BG meter experiment using handheld glucometers to test for blood glucose levels. I made two series of tests. The first round was done between July 31 and Aug. 7, 2001. The second round, was done between Aug. 20 to Aug. 24.

Method

The blood samples used for the Elite and Freestyle were all obtained from ear pricks. The following results were obtained from the same blood sample (except for two tests - the first test in each series used samples from a puncture made about 30 seconds later, 1/8" over). After getting a good size drop of blood, I used the Elite to sip a sample, then the Freestyle. The time difference in taking the two samples was about 3 - 5 seconds.

The vet's Lab meter and Handheld samples were venous samples taken a few seconds before the ear prick sample.

After obtaining the first test variance, I called the customer service 800-number for each company. I asked each representative to walk me through all possible home accuracy tests to determine if the meters were not calibrated properly. Each meter passed it's tests with flying colors.

Note: Neither company guarantees results using non-human blood and both representatives made that very clear. These results are solely a record of my personal experiments using the meters under home usage conditions when testing BG levels in my diabetic cat, Punkin.

Conclusion

The Freestyle was consistently way lower (up to 170 points lower) than the Elite at higher BG readings. The lower the readings, the less was the difference.

Your milage may vary.

You can view the results of Hope's side-by-side tests of the Elite, OneTouch Ultra, and AccuChek Advantage at: http://www.gorbzilla.com/meter_comparisons.htm. (Note: my side-by-side tests with the OneTouch and the Elite also found the OneTouch produced slightly higher values).

Graphical Representation

The purple line represents the relationship between the Freestyle and the Elite; it's called the least-squares line or the regression line. (It also gives us a clue as to how to correct the Freestyle values for those of us who own the Freestyle). The black line represents where the points would be if the Elite and the Freestyle gave the same values. So this graph makes the point that, in this test, the Freestyle values are *always* below the Elite values. But they are tightly correlated, which means that - between Terry's two meters - the value from the Elite can be approximately estimated by multiplying the Freestyle value by 1.387 and subtracting 19.

Test Data

Round 1, July 31 to August 7, 2001

I contacted the Therasense people after this test and asked for a replacement meter. Perhaps this is a defective unit, despite the fact that it passed the normal home calibration checks.

However, Therasense refused to troubleshoot the meter or replace it on the grounds that it was being used to test feline blood, and they do not support such usage.

Round 2, August 20 to August 24, 2001

During this round of testing, Punkin was on a lower dose of insulin, so his BG values were higher.