We used the digital array to measure the CYP2D6 copy numbers of three DNA samples from ParagonDX (Morrisville, NC). The CYP2D6 genotypes of these DNA samples had been characterized (Table 1 ). The samples were STA-treated (see Figure 3 and Materials and methods section) and the products were analyzed using five panels each on the digital arrays. The relative copy numbers of these three samples are 0, 0.49 and 0.98, respectively, highly consistent with their assumed CYP2D6 diploid copy numbers (0, 1 and 2) based upon their genotypes.