NIST Mixed Stain Study 3:  DNA Quantitation Accuracy and Its Influence on Short Tandem Repeat Multiplex Signal Intensity

The Mixed Stain Study 3 (MSS3) interlaboratory challenge exercise evaluated the 2001 performance of STR multiplex DNA typing systems using a set of seven DNA extracts of designed concentration and composition. This initial report focuses on the linkages connecting the measurement of the concentration of DNA ([DNA]) to the observed STR multiplex signal intensities. There is a causal relationship between [DNA] measurement accuracy and the efficiency of STR multiplex analysis. There are no intrinsic measurement performance differences among the [DNA] measurement technologies reported. However, there are large differences in the efficiencies of amplification, separation, and detection among participants using the same nominal measurement systems.