Test results II
In one study (1) three plate based cyclers were compared, and at target concentrations corresponding to a Ct = 20 the SEM was 0.14, 0.15 and 0,5 for Stratagene Mx3005p, RotorGene and ABI 7700, respectively.
Our observation might therefore reflect a general difference between plate- and air based cyclers.
We believe that there are two main reasons for the much higher precision of the Lightcycler. First there is no heating plate which can create temperature inhomogeniety, but only one reaction chamber where all the samples are placed. This ensures that all samples are at the same temperature, especially since they rotate and a powerful fan eliminates any temperature gradient which might build up in the chamber. Second, only one sensor is used for all fluorescence readings. Each sample in turn passes over the same sensor, which eliminates any difference there may be in a system with multiple sensors (as in plate based cyclers).
1) Reynisson E, Josefsen MH, Krause M, Hoorfar J. Evaluation of probe chemistries and platforms to improve the detection limit of real-time PCR. J Microbiol Methods. 2006;66:206-16.
