Signal Measurement and Reaction Dynamics
Light Scatter Signal Development
IMMAGE 800 Operations Manual A11403
Theory of Operations
September 2016
Page 3-3
3
Signal Measurement and Reaction Dynamics
Light Scatter Signal Development
During an antigen-antibody reaction, immunoprecipitin complexes are formed.
In rate nephelometry, the light scattered at 90° increases as the complexes are formed.
In rate turbidimetry, the light intensity at 0° decreases as the complexes are formed.
This decrease is converted to an increasing scatter signal by the formula:
Rate nephelometry and rate turbidimetry give the same signal as illustrated in
Figure 3.2.
Figure 3.2
Scatter Signal versus Time for Rate Nephelometry and Rate
Turbidimetry
Rate Determination
The system monitors scatter signal from the antigen antibody reaction at 5 second time
intervals. At the end of the reaction, the system mathematically calculates the rate of
change of the scatter signal.
1. X = Increasing time
2. Y = Increasing scatter signal
3. Buffer Addition
4. Sample Addition
5. Antibody Addition
E011367L.EPS
light intensity
initial light intensity
⎧
⎩
⎫
⎭
scatter signal = -Log
10
X
Y
A011368L.EPS
3
1
4
2
5