Piccolo Xpress Manuel De L'opérateur page 92

8.2.2 Endpoint Reactions
Reagents, samples, and chromophores all absorb light in endpoint reactions. Light absorption by the
samples must be subtracted so that the analyte concentration can be isolated. The absorbance of the
sample is measured in a sample blank cuvette. Some chemistries employ a generic sample blank and
others (such as total bilirubin) use a dedicated sample blank. The intensity of the light passing through
the sample blank cuvette (I
through the reaction cuvette.
The equation for endpoint reactions is:
where:
I = Intensity of light transmitted through the sample blank cuvette at wavelength 1
λ 1SC
I = Intensity of light transmitted through the sample blank cuvette at wavelength 2
λ 2SC
I = Other intensities as described above
λ XX
The net absorbance is converted to analyte concentration using data encoded in the bar code printed
on the bar code ring.
8-4
, I ) is measured at the same wavelengths as is the light passing
λ 1SC λ 2SC
Operating Principles