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.r5.examples derivation: constraint name: timeOffset 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: 4.5.0 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/observation-timeOffset base: http://hl7.org/fhir/StructureDefinition/Extension version: 4.5.0 required: [value, valueInteger]