FHIR R5 Observation resource.

Measurements and assertions made about a patient, device, or other subject. The primary resource for representing lab results.

https://www.hl7.org/fhir/R5/observation.html

Status codes: registered | preliminary | final | amended | corrected |

          cancelled | entered-in-error | unknown

Polymorphic value[x]

The result value is stored as a tagged tuple on the value field:

{:quantity, %Quantity{value: 14.5, unit: "g/dL", ...}}
{:codeable_concept, %CodeableConcept{...}}
{:string, "Positive"}
{:boolean, true}
{:integer, 42}
{:range, %Range{...}}
{:ratio, %Ratio{...}}
{:sampled_data, map()}
{:time, "09:30:00"}
{:date_time, "2024-01-15T09:30:00Z"}
{:period, %Period{...}}

Reference ranges

The reference_range field holds normal ranges for the result. Each entry can have low, high, normal_value, type, applies_to, age, and text.

Example

alias FhirEx.Resources.Observation
alias FhirEx.Types.{Reference, CodeableConcept, Coding, Quantity}

observation = %Observation{
  id: "obs-001",
  status: "final",
  category: [
    %CodeableConcept{
      coding: [%Coding{
        system: "http://terminology.hl7.org/CodeSystem/observation-category",
        code: "laboratory"
      }]
    }
  ],
  code: %CodeableConcept{
    coding: [%Coding{system: "http://loinc.org", code: "718-7", display: "Hemoglobin [Mass/volume] in Blood"}],
    text: "Hemoglobin"
  },
  subject: %Reference{reference: "Patient/patient-001"},
  effective: {:date_time, "2024-01-15T09:30:00Z"},
  issued: "2024-01-15T10:00:00Z",
  value: {:quantity, %Quantity{value: 14.5, unit: "g/dL", system: "http://unitsofmeasure.org", code: "g/dL"}},
  reference_range: [
    %{
      low: %Quantity{value: 12.0, unit: "g/dL", system: "http://unitsofmeasure.org", code: "g/dL"},
      high: %Quantity{value: 17.5, unit: "g/dL", system: "http://unitsofmeasure.org", code: "g/dL"},
      text: "12.0 - 17.5 g/dL"
    }
  ]
}