Each lot of Tth DNA Polymerase is assayed for activity on activated DNA. A function test is performed using ?DNA, as well as human genomic DNA. Performance in RT/PCR is assayed using total mouse RNA and primers specific for ?-actin. Each lot of Tth DNA Polymerase is tested for the absence of contaminating activities like exo- and endonucleases and nicking activities according to the current Quality Control procedures. A unique self-priming assay ensures the absence of contaminating DNA according to the current Quality Control procedures.