Abaxis VetScan vs2 - Endpoint Reactions

9-4 Principles of Procedure and Operation
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
O1SC
, I
O2SC
) is measured at the same wavelengths as
is the light passing through the reaction cuvette.
The equation for endpoint reactions is:
where:
I
O1SC
= Intensity of light transmitted through the sample blank cuvette at wavelength 1
I
O2SC
= Intensity of light transmitted through the sample blank cuvette at wavelength 2
I
OXX
= Other intensities are the same as described above
The net absorbance is converted to analyte concentration using data encoded in the bar code
printed on the bar code ring.
(I
λ1RC
- I
λ1
0
) / (I
λ2RC
- I
λ2
0
)
(I
λ1OC
- I
λ1
0
) / (I
λ2OC
- I
λ2
0
)
A = -log