Accu-Chek Performa Owner's Booklet page 68

Measuring Principle
The enzyme on the test strip, glucose dehydrogenase, in the presence of the coenzyme
(PQQ), converts the glucose in the blood sample to gluconolactone. This reaction creates a
harmless DC electrical current that your meter interprets for your blood glucose. The sample
and environmental conditions are also evaluated using a small AC signal.
Blood glucose concentrations may be measured in whole blood or plasma. Although you
always apply whole blood to the test strip, your meter displays blood glucose results that
relate to plasma. Please refer to the package insert for information on how the system
works, on the test principle and on reference methods.
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