RADIOMETER FLEX ABL90, Reference Manual

Page: 162 / 346

5. Sensors and optical system ABL90 FLEX reference manual
5-34
 The baseline is extrapolated throughout the whole electrode calibration or
sample measurement period, and represents the zero current time function
 The I
0
baseline is used in the determination of the sensitivity of the
cGlu/cLac sensor
Calibration of the metabolite sensors
The sensitivity of the cGlu and cLac sensors is calculated by measuring the
current from CAL 3 then subtracting the zero current as measured from CAL 1.
CAL 3 has a nominal glucose concentration of 10 mmol/L and a nominal lactate
concentration of 10 mmol/L. The precise values are specific to the individual lot
of the solution pack and are contained in the solution pack smart chip.
The current at the cGlu and cLac sensors with CAL 3 in the measuring chamber
is measured at regular intervals after the chamber is filled with solution. The
current, when signal stability is reached, is used to determine the sensitivity of
the cGlu or cLac sensor.
The sensitivity of the cGlu or cLac sensor is calculated as follows:
cal3 0
cal
I I
S
c


where I
0
is the zero current estimated to the time of measurement from the 8
samples taken on CAL 1 (rinse).
Status is defined as I
0
.
Sensitivity