The presence of intrinsic PCR inhibitors in some sample types, such as those from blood or fixed tissues, can prevent the direct amplification of DNA from these samples. DNA can be purified prior to PCR via a variety of extraction techniques but these methods can be costly, time intensive and result in significant sample loss. Extraction-free PCR typically benefits from a polymerase that is resistant to inhibitors, allowing for robust amplification of source DNA without additional extraction steps.