How many PCR cycles are typically used in a thermal cycler program for clinical HLA typing?

In clinical HLA typing, the typical number of PCR cycles used in a thermal cycler program is around 30 cycles. This is based on the need for sufficient amplification of DNA to generate enough material for accurate typing and analysis. Each cycle of PCR consists of denaturation, annealing, and extension, which double the amount of DNA with each completed cycle.

Using around 30 cycles strikes a balance between generating enough DNA for analysis while preventing the onset of non-specific amplification and PCR artifacts that may occur with too many cycles. This level of cycles is often sufficient to achieve the sensitivity and specificity required for HLA typing, making it a standard practice in the laboratory setting.