Figure 2From: Determination of PCR efficiency in chelex-100 purified clinical samples and comparison of real-time quantitative PCR and conventional PCR for detection of Chlamydia pneumoniaeEffect of difference in efficiency between standard samples and samples. This figure illustrates the error in determination of concentration by real-time PCR at cycle no. 30 when the efficiencies differ between standard samples and samples. Number of cycles: n, Efficiency standard samples: Estd, efficiency reference samples: Ers, Number of amplicons at cycle n: Nn, Number of amplicons at cycle zero: N0. When the two equations are divided by eachother it is seen that there is an 23-fold underestimation of the concentration when Estd = 2.0 and Ers = 1.8. From this calculation it is also evident that at higher cycle number the error in concentration determination is larger.Back to article page