Rotation Algorithm for Determining Cycle Thresholds in Real-Time Polymerase Chain Reactions

The real time-polymerase chain reaction (RT-PCR) is a methodology that is widely used to amplify and quantify specific sections of nucleic acid strands. A key aspect of RT-PCR is to determine the reaction cycle that produces a positive PCR signal. This cycle is proportional to the relative concentration of nucleic acid and produces a linear curve when plotted vs. the log of the sample concentration. The cycle that produces a positive PCR signal is called the elbow or more precisely the cycle threshold (Ct) value. This paper describes a novel rotation algorithm that determines the Ct value and is less susceptible to signal interferences.