PGx sampling method and genotype efficiency call rate. (a) Call rate distribution by sample type: Single nucleotide polymorphism data from saliva derived or blood derived DNA was generated using the Illumina Human OmniQuad BeadChip. One hundred ninety-eight (36%) of 551 saliva samples tested failed genotyping according to manufacturer defined QC standards compared to 11 of the 352 (3%) blood DNA samples (p < 0.0005). Similarly saliva DNA samples were more likely than blood DNA samples to fail genotyping QC criteria on the FRET-based KASPar platform. Eighty-two of 447 saliva DNA samples (18.3%) tested failed genotyping QC standards compared to 21 of 331 (6.3%) blood DNA samples (p < 0.001; not shown). (b) Genotype call rate and saliva collection volume: Saliva DNA samples where the collection volume was 0.5 mL were more likely to provide low quality genotype data on both OmniQuad and FRET-based genotyping platforms.