Real-time quantitative PCR technology is a nucleic acid quantification technology developed by American PE (Perkin Elmer) company in 1995. It has achieved a leap from qualitative to quantitative PCR, based on fluorescence energy transfer technology (FRET) The fluorescent signal of the PCR process is used to know the initial concentration of the target gene. Real-time quantitative PCR technology realizes its quantitative function by adding fluorescently labeled probes on the basis of conventional PCR, and has the characteristics of high sensitivity, high specificity and high accuracy. At present, it has been used in many fields such as pathogen determination, tumor gene detection, immunoassay, gene expression, mutation and polymorphism research. 

The application of real-time quantitative PCR simplifies the detection process. It has fast response, high sensitivity, strong specificity, good reproducibility, and closed-tube operation. It has been made into kits by many domestic and foreign manufacturers and is widely used in clinical practice.

This technology is a new method for DNA detection and absolute quantification. Unlike traditional quantitative PCR (qPCR) technology, digital PCR is to convert the exponential multiple signal of traditional PCR into a linear digital signal, read the value through a specific instrument, and use statistical methods to analyze PCR products.

The current digital PCR technology includes microdrop and microwell detection platforms. The principle is to divide the reaction system containing nucleic acid molecules into thousands of single molecule systems, and then perform single-molecule template PCR amplification and accurate quantification of nucleic acid copy number .