Roche Cedex Bio User Manual

Roche Diagnostics
C-14
Operator’s Manual · Version 3.4
8 Data analysis methods Cedex Bio analyzer
Photometric measurements
Antigen Excess check
This check is carried out with controls and samples. It can be used to determine an
antigen excess. The binding of an antigen to a specific antibody produces cross-
linked complexes which scatter light.
In the presence of excess antibody, the absorbance increases with increasing antigen
concentration. With antigen excess, the absorbance will decrease with increasing
antigen concentration so that the same refers to two different concentrations.
The point at which the signal begins to decrease is the beginning of the antigen excess
region of the Heidelberger Curve. The Antigen (AG) Rate should be determined with
the Antigen Excess check first.
Determination of antigen (AG)
rates
The test parameters AG First, AG Last and the Endpoint calculation model are
required for determining antigen rates.
The AG rate of the standards is determined by the mean of the replicate AG rates.
ΔA
300
0
250
200
150
50
100
0 1020304050607080
Antibody excess Antigen excess
B
C
g/L
Rate
Antigen Concentration

Roche Cedex Bio Specifications

General

Brand	Roche
Model	Cedex Bio
Category	Measuring Instruments
Language	English