description: A specific offset time in milliseconds from the stated time in the Observation.appliesDateTime to allow for representation of sequential recording of sampled data from the same lead or data stream. For example, an ECG recorder may record sequentially 3 leads four time to receive 12-lead ECG, see [ISO 22077](https://www.iso.org/obp/ui/#iso:std:61871:en). package_name: rs/hl7.fhir.uv.extensions derivation: constraint name: ObsTimeOffset type: Extension elements: extension: {index: 0} url: pattern: {type: uri, value: 'http://hl7.org/fhir/StructureDefinition/observation-timeOffset'} type: uri index: 1 value: choices: [valueInteger] index: 3 valueInteger: {type: integer, choiceOf: value, index: 4} package_version: 5.1.0-cibuild extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/observation-timeOffset base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.1.0-cibuild required: [value, valueInteger]