We agree with the proposed guidance and framework on genetic reporting; however, we note the incomplete status of Appendix D: External Coding Systems. Further guidance is requested on the standardization of identifiers used to define pharmacogenetic phenotype and genotype as part of the Diagnostic Report metadata. It appears that LOINC is suggested as an example identifier used to direct the various Genetic Impacts (eg, metabolism impact, transporter impact, etc). However, LOINC is presently insufficient in terms of scope and hierarchical detail as it does not comprehensively address the spectrum of common metabolic phenotypes and the underlying genotypes associated. It is also unclear whether LOINC is being recommended as the preferred identifier (for pharmacogenomics), or whether other systems are being evaluated as part of Appendix D. Further guidance on what HL7 is recommending as the standard is critical towards broad integration of pharmacogenomic clinical screening across various healthcare systems.