Frequency of NUDT15 diplotypes associated with a nonstandard thiopurine dosing recommendation as per published PGx guidelines and drug label annotations, stratified by genetic ancestral group. The *1/*3 diplotype is associated with intermediate metabolizer status. The *3/*3 diplotype is associated with poor metabolizer status. Abbreviations: AFR, African; AMR, Admixed American; EAS, East Asian; EUR, European; SAS, South Asian. The “unknown” ancestral group corresponds to samples whereby ancestry could not be resolved by principal component analysis due to possible genetic admixture.