What is the meaning of the CT value?
CT is the abbreviation for Threshold Cycle and is defined as the calculated cycle number at which the PCR product crosses a threshold of detection. This threshold line is either automatically set by the software algorithm of the real-time PCR instrument or can be manually adjusted. The CT values are essential for quantitation since the standard curve is generated by plotting the CT values versus the logarithmic concentration. A positive unknown sample will also be assigned a specific CT value and by comparison with the standard curve a particular concentration can be calculated