Persuasive with mod Add to both the diagnosticImplication and therapeuticImplication pages, a section 'Differentiating AND vs OR': There are several cases where it is necessary to differentiate 'AND' conditions (e.g. both drug X AND drug Y, in combination, are indicated in the presence of a variant) vs. 'OR' conditions (e.g. either drug X OR drug Y are indicated in the presence of a variant).  This situation is not unique to genomic implications, and arises elsewhere within FHIR (e.g. FHIR Search ) and outside of FHIR (e.g. Clinvar submission API , condition set). To be consistent with other precedents: Where Diagnostic and Therapeutic implications have fields with cardinality >1, the inclusion of multiple values within a field shall indicate an 'AND' condition. An 'OR' condition is represented by multiple observation instances . Implication fields affected by this guidance include:  Therapeutic implications: derivedFrom, evidence-level, phenotypic-treatment-context, medication-assessed, therapy-assessed, predicted-therapeutic-implication. Diagnostic implications: derivedFrom, evidence-level, predicted-phenotype, functional-effect. For example, assume Variant X is pathogenic for Disease Y AND Disease Z in combination. This would be a single diagnostic implication, where predicted-phenotype is a list containing both Disease Y and Disease Z. If on the other hand, Variant X might be pathogenic for Disease Y alone, or Disease Z alone, this would be two diagnostic implications, one containing a predicted-phenotype of Disease Y, and the other containing a predicted-phenotype of Disease Z.