Molecular Devices FLIPR Tetra, User Manual

Page: 278 / 302

Data Processing Algorithms
278 0112-0109 H
Positive Control Scaling
The positive control algorithm compares the percent change in
fluorescence counts of the positive control wells with all wells. This
algorithm facilitates comparisons of results between data runs ( i.e.,
different plates) by controlling factors such as cell density, cell
response, laser power, or exposure time. This algorithm also makes
EC
50
comparisons easier.
Determining the Positive Control Scaling
1. The means of all samples of the positive control wells are
calculated.
2. The difference in fluorescence counts between Sample 1 and all
of the samples is calculated.
3. The greatest difference is determined.
4. 100 is divided by the greatest difference in fluorescence counts
(determined above) to give the positive control correction factor
e.g., 100/42296 = 0.0024.
5. All samples are multiplied by the correction factor 0.0024 (see
the following table).
Sample Time
Well
Mean
Difference
from
Sample 1
A7 + Ctrl A8 + Ctrl A9 + Ctrl
1 0 8900 8930 8961 8930 0
2 5 8370 9027 9177 8858 -72
3 10 8547 9027 9585 9053 123
4 20 50223 48391 55064 51226 42296
5 25 45755 45590 49955 47100 38170
6 30 43165 46502 49955 46541 37610
Sample Time
Well
A1
– Ctrl
A2
– Ctrl
A3
– Ctrl
A4
Exp
A5
Exp
A6
Exp
A7
+ Ctrl
A8
+ Ctrl
A9
+ Ctrl
1 0 21 21 21 21 21 21 21 21 21
2 5 21 21 21 21 20 21 20 21 23
3 10 22 21 20 22 20 22 20 21 23