Rotor-Gene Q MDx CE User Manual 02/2022
95
Given an M value of –3.322, the calculations are as follows:
Exponential amplification: 10
(–1/–3.322)
= 2
Reaction efficiency: [10
(–1/–3.322)
] – 1 = 1
As an alternative example: an M value of 3.8 means that the reaction has an exponential
amplification of approximately 1.83 and a reaction efficiency of 0.83 (or 83%).
Offset
In a formula describing the relationship between 2 variables, the offset is expressed with the letter
B (y = Mx + B). The offset is also sometimes referred to as the intercept. B represents the C
T
for a
given concentration of 1 unit. By substituting 1 into the concentration formula as shown below:
C
T
= log(1) * M + B
C
T
= 0 * M + B
The result is C
T
= B
The intercept can change from run to run and is a less stable measurement than the gradient. For
this reason, the gradient is analyzed more frequently than the intercept.
Main window
The main window displays the amplification plots on a log scale.
Clicking
Linear Scale
at the bottom of the window changes the scale from the log scale to the linear
scale and vice versa. Changing between these scales only alters the display of the graphs, not the
calculations. This can be verified by use of the pinpointer tool by right-clicking on the graph and
selecting
Show pinpointer
. Using a log scale, smaller values are more visible on the graph whereas
a linear scale facilitates a view of the entire reaction.
Note
: Amplification plots update in real time as the Rotor-Gene Q MDx is actively acquiring data
during a run. This real-time monitoring of data enables the user to see results as soon as the curves
show exponential growth. Preliminary conclusions can be drawn and decisions made for the next
run.