According to the purpose of DNA amplification and detection standards, PCR system can be divided into ordinary PCR machine, gradient PCR machine, in-situ PCR machine, and real-time fluorescence quantitative PCR machine. For ordinary PCR machine, the temperature control indicators mainly refer to the accuracy, uniformity, and temperature rise and fall speed.

The temperature accuracy refers to the consistency of the sample well temperature and the set temperature, which is directly related to the success or failure of the experiment. If the problem of misoperation during sample addition is ruled out, the most important thing for PCR reaction is the accuracy of temperature control. Temperature uniformity refers to the temperature difference between sample wells, which is related to the consistency of the reaction results in different sample wells.

The temperature rise and fall speed refers to the speed of temperature rise and fall in different PCR reaction stages. Obviously, the faster temperature rise and fall speed can shorten the time required for the reaction, and can effectively reduce the non-specific binding caused by the heating and cooling process, shorten the reaction time, and improve the specificity of the PCR reaction.

However, it is worth noting that the temperature rise and fall speed of PCR machine is not the same thing as the heating and cooling speed of the sample in the sample tube, because the tightness of the contact between the sample tube and the base, the thermal conductivity, and the mutual influence of the adjacent sample tubes will affect the actual heating and cooling rate of the sample.