RADIOMETER ABL800 FLEX, Reference Manual

Page: 56 / 206

ABL800 FLEX Reference Manual 2. Amperometric measuring principles
Metabolite electrodes,
Continued
Measurement The glucose/lactate concentration in a sample is calculated from the following
equation:
Sens
(final) I I(sample)
X(sample)
0
−
=
c
where:
I(sample) = Current of the metabolite electrode measured on the
sample.
I
0
(final) = Extrapolated final zero current value of the metabolite
electrode at the time of the last sample updating.
Sens = Relative sensitivity of the metabolite electrode.
Corrections The measured metabolite concentration is corrected for systematic deviations from
the reference method by the following equations:
Equation A:
L) (195 1 L) (195 0 L 195
X(sample) A corr) X(sample,
µ µ µ
A c c
+ × =
and
Equation B:
c X(sample,corr)
micromode
= A
0,micromode
×
c X(sample,corr)
195
µ
L
+
A
1,mocromode
where:
c X(sample) = uncorrected measured metabolite concentration from a sample
c X(sample,
corr)
= corrected measured metabolite concentration from a sample
A
0
= instrument-dependent correction factor
A
1
= instrument-dependent cut-off
When an additional correction is needed, equation A is first used together with the
constants for the 195
µ
L mode. Then the obtained results are put back into
equation B as c X(sample) and then treated again, using the constants for the
specific mode.
Note that subscript “195
µ
L” in the equations above is used for convenience sake
and stands for “FLEXMODE (no message)”, “FLEXMODE (message 874)”, and
“FLEXMODE (message 873)”.
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