August 4, 2006

British Meters are Whole Blood Calibrated!

I first saw someone post that British blood sugar meters still read in whole blood calibration rather than the plasma equivalent calibration now used in the U.S. on Dr. Bernstein's discussion board which you'll find here .

I checked this out by posting a question on and sure enough, it turns out that it was true. The Roche meters (and strips) sold in the UK are whole blood calibrated, while those sold in the U.S. are plasma calibrated. That includes all the Accuchek meters.

Why does this matter? Because for the same blood sample, meters that read in whole blood calibration give readings 12% lower than those that read in plasma calibration. So a Brit who reads online that a healthy blood sugar target according to the AACE is under 140 mg/dl or 7.7 mmol/l and then gets a reading of 7.6 on his Accuchek meter is happy. He'd be a lot less happy if he realized that 7.6 on the Accuchek would be 8.5 on an American Accuchek, which is, of course, what the AACE is referring to.

Similarly, the 200 mg/dl or 11 mmol/l that is diagnostic for diabetes on a random check is also a plasma calibrated value. The same reading would be 9.9 mmol/l on a blood calibrated meter.

And, just to make it really confusing, while some web sites claim that the Ultra sold in the UK is plasma calibrated, like those in the U.S., Lifescan's UK site specifically says that the strips sold for their Ultra meters in the UK are whole blood calibrated.

Here's a government pamphlet explaining the situation (though it incorrectly identifies the difference as 11% when it has been reported elsewhere as 12%.
UK Pamphlet

Here's the Lifescan link with conflicting information: Lifescan UK Info

From what the Brits have posted when this discussion comes up, it appears that their medical professionals are NOT aware of this issue at all.

If you are in the UK and attempting to maintain healthy blood sugar levels, be sure to convert your readings to plasma readings by multiplying them by 1.12!