NP Core Blood Pressure Observation

Sets minimum expectations for blood pressure observations in the NP Core. Derives from the FHIR Blood Pressure vital signs profile, which fixes the panel LOINC code (85354-9), the systolic (8480-6) and diastolic (8462-4) component codes, and constrains the component values to UCUM mm[Hg].

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Canonical URL: http://fhir.digitalhealth.gov.np/core/StructureDefinition/np-core-blood-pressure-observation
Resource / type: Observation
Based on: http://hl7.org/fhir/StructureDefinition/bp
Claim conformance: Put the canonical URL in meta.profile of each instance.

Required elements

“Always” means the element must be present in every instance. Otherwise it is required only when its parent element is present.

Element	Card.	When
`Observation.status` registered \| preliminary \| final \| amended +	1..1	Always
`Observation.category` Classification of type of observation	1..*	Always
`Observation.category:VSCat` Classification of type of observation	1..1	Always
`Observation.category:VSCat.coding` Code defined by a terminology system	1..*	Always
`Observation.category:VSCat.coding.system` Identity of the terminology system	1..1	Always
`Observation.category:VSCat.coding.code` Symbol in syntax defined by the system	1..1	Always
`Observation.code` Blood Pressure	1..1	Always
`Observation.code.coding` Code defined by a terminology system	1..*	Always
`Observation.code.coding:BPCode` Code defined by a terminology system	1..1	Always
`Observation.code.coding:BPCode.system` Identity of the terminology system	1..1	Always
`Observation.code.coding:BPCode.code` Symbol in syntax defined by the system	1..1	Always
`Observation.subject` Who and/or what the observation is about	1..1	Always
`Observation.effective[x]` Often just a dateTime for Vital Signs	1..1	Always
`Observation.component` Used when reporting systolic and diastolic blood pressure.	2..*	Always
`Observation.component.code` Type of component observation (code / type)	1..1	Always
`Observation.component:SystolicBP` Used when reporting systolic and diastolic blood pressure.	1..1	Always
`Observation.component:SystolicBP.code` Type of component observation (code / type)	1..1	Always
`Observation.component:SystolicBP.code.coding` Systolic Blood Pressure	1..*	Always
`Observation.component:SystolicBP.code.coding:SBPCode` Systolic Blood Pressure	1..1	Always
`Observation.component:SystolicBP.code.coding:SBPCode.system` Identity of the terminology system	1..1	Always
`Observation.component:SystolicBP.code.coding:SBPCode.code` Symbol in syntax defined by the system	1..1	Always
`Observation.component:SystolicBP.value[x].value` Numerical value (with implicit precision)	1..1	If parent present
`Observation.component:SystolicBP.value[x].unit` Unit representation	1..1	If parent present
`Observation.component:SystolicBP.value[x].system` System that defines coded unit form	1..1	If parent present
`Observation.component:SystolicBP.value[x].code` Coded responses from the common UCUM units for vital signs value set.	1..1	If parent present
`Observation.component:DiastolicBP` Used when reporting systolic and diastolic blood pressure.	1..1	Always
`Observation.component:DiastolicBP.code` Type of component observation (code / type)	1..1	Always
`Observation.component:DiastolicBP.code.coding` Diastolic Blood Pressure	1..*	Always
`Observation.component:DiastolicBP.code.coding:DBPCode` Diastolic Blood Pressure	1..1	Always
`Observation.component:DiastolicBP.code.coding:DBPCode.system` Identity of the terminology system	1..1	Always
`Observation.component:DiastolicBP.code.coding:DBPCode.code` Symbol in syntax defined by the system	1..1	Always
`Observation.component:DiastolicBP.value[x].value` Numerical value (with implicit precision)	1..1	If parent present
`Observation.component:DiastolicBP.value[x].unit` Unit representation	1..1	If parent present
`Observation.component:DiastolicBP.value[x].system` System that defines coded unit form	1..1	If parent present
`Observation.component:DiastolicBP.value[x].code` Coded responses from the common UCUM units for vital signs value set.	1..1	If parent present

Must-support elements

If your system has this data it SHALL send it, and receivers SHALL process it. Must-support does not by itself make an element mandatory.

Observation.status
Observation.category
Observation.category:VSCat
Observation.category:VSCat.coding
Observation.category:VSCat.coding.system
Observation.category:VSCat.coding.code
Observation.code
Observation.subject
Observation.encounter
Observation.effective[x]
Observation.value[x]
Observation.value[x]:valueQuantity
Observation.dataAbsentReason
Observation.component
Observation.component.code
Observation.component.value[x]
Observation.component.dataAbsentReason
Observation.component:SystolicBP
Observation.component:SystolicBP.code
Observation.component:SystolicBP.value[x]
Observation.component:SystolicBP.value[x].value
Observation.component:SystolicBP.value[x].unit
Observation.component:SystolicBP.value[x].system
Observation.component:SystolicBP.value[x].code
Observation.component:SystolicBP.dataAbsentReason
Observation.component:DiastolicBP
Observation.component:DiastolicBP.code
Observation.component:DiastolicBP.value[x]
Observation.component:DiastolicBP.value[x].value
Observation.component:DiastolicBP.value[x].unit
Observation.component:DiastolicBP.value[x].system
Observation.component:DiastolicBP.value[x].code
Observation.component:DiastolicBP.dataAbsentReason

Fixed and pattern values

Element	Value
`Observation.category:VSCat.coding.system`	http://terminology.hl7.org/CodeSystem/observation-category
`Observation.category:VSCat.coding.code`	vital-signs
`Observation.code.coding:BPCode.system`	http://loinc.org
`Observation.code.coding:BPCode.code`	85354-9
`Observation.component:SystolicBP.code.coding:SBPCode.system`	http://loinc.org
`Observation.component:SystolicBP.code.coding:SBPCode.code`	8480-6
`Observation.component:SystolicBP.value[x].system`	http://unitsofmeasure.org
`Observation.component:SystolicBP.value[x].code`	mm[Hg]
`Observation.component:DiastolicBP.code.coding:DBPCode.system`	http://loinc.org
`Observation.component:DiastolicBP.code.coding:DBPCode.code`	8462-4
`Observation.component:DiastolicBP.value[x].system`	http://unitsofmeasure.org
`Observation.component:DiastolicBP.value[x].code`	mm[Hg]

Terminology bindings

required: codes SHALL come from the value set · extensible: use the value set if a suitable code exists · preferred / example: guidance only.

Element	Strength	Value set
`Observation.language`	preferred	http://hl7.org/fhir/ValueSet/languages
`Observation.status`	required	http://hl7.org/fhir/ValueSet/observation-status
`Observation.category`	preferred	http://hl7.org/fhir/ValueSet/observation-category
`Observation.category:VSCat`	preferred	http://hl7.org/fhir/ValueSet/observation-category
`Observation.code`	extensible	http://hl7.org/fhir/ValueSet/observation-vitalsignresult
`Observation.dataAbsentReason`	extensible	http://hl7.org/fhir/ValueSet/data-absent-reason
`Observation.interpretation`	extensible	http://hl7.org/fhir/ValueSet/observation-interpretation
`Observation.bodySite`	example	http://hl7.org/fhir/ValueSet/body-site
`Observation.method`	example	http://hl7.org/fhir/ValueSet/observation-methods
`Observation.referenceRange.type`	preferred	http://hl7.org/fhir/ValueSet/referencerange-meaning
`Observation.referenceRange.appliesTo`	example	http://hl7.org/fhir/ValueSet/referencerange-appliesto
`Observation.component.code`	extensible	http://hl7.org/fhir/ValueSet/observation-vitalsignresult
`Observation.component.value[x]`	extensible	http://hl7.org/fhir/ValueSet/ucum-vitals-common
`Observation.component.dataAbsentReason`	extensible	http://hl7.org/fhir/ValueSet/data-absent-reason
`Observation.component.interpretation`	extensible	http://hl7.org/fhir/ValueSet/observation-interpretation
`Observation.component:SystolicBP.code`	extensible	http://hl7.org/fhir/ValueSet/observation-vitalsignresult
`Observation.component:SystolicBP.value[x]`	extensible	http://hl7.org/fhir/ValueSet/ucum-vitals-common
`Observation.component:SystolicBP.value[x].comparator`	required	http://hl7.org/fhir/ValueSet/quantity-comparator
`Observation.component:SystolicBP.dataAbsentReason`	extensible	http://hl7.org/fhir/ValueSet/data-absent-reason
`Observation.component:SystolicBP.interpretation`	extensible	http://hl7.org/fhir/ValueSet/observation-interpretation
`Observation.component:DiastolicBP.code`	extensible	http://hl7.org/fhir/ValueSet/observation-vitalsignresult
`Observation.component:DiastolicBP.value[x]`	extensible	http://hl7.org/fhir/ValueSet/ucum-vitals-common
`Observation.component:DiastolicBP.value[x].comparator`	required	http://hl7.org/fhir/ValueSet/quantity-comparator
`Observation.component:DiastolicBP.dataAbsentReason`	extensible	http://hl7.org/fhir/ValueSet/data-absent-reason
`Observation.component:DiastolicBP.interpretation`	extensible	http://hl7.org/fhir/ValueSet/observation-interpretation

Rules (invariants)

vs-2 If there is no component or hasMember element then either a value[x] or a data absent reason must be present.

FHIRPath

(component.empty() and hasMember.empty()) implies (dataAbsentReason.exists() or value.exists())

vs-1 if Observation.effective[x] is dateTime and has a value then that value shall be precise to the day

FHIRPath

$this is dateTime implies $this.toString().length() >= 10

obs-3 Must have at least a low or a high or text

FHIRPath

low.exists() or high.exists() or text.exists()

vs-3 If there is no a value a data absent reason must be present

FHIRPath

value.exists() or dataAbsentReason.exists()

Official examples

Observation/ExampleNPCoreBloodPressureObservation

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{
  "resourceType": "Observation",
  "id": "ExampleNPCoreBloodPressureObservation",
  "meta": {
    "profile": [
      "http://fhir.digitalhealth.gov.np/core/StructureDefinition/np-core-blood-pressure-observation"
    ]
  },
  "status": "final",
  "category": [
    {
      "coding": [
        {
          "system": "http://terminology.hl7.org/CodeSystem/observation-category",
          "code": "vital-signs",
          "display": "Vital Signs"
        }
      ]
    }
  ],
  "code": {
    "coding": [
      {
        "system": "http://loinc.org",
        "code": "85354-9",
        "display": "Blood pressure panel with all children optional"
      }
    ]
  },
  "subject": {
    "reference": "Patient/ExampleNPCorePatient"
  },
  "encounter": {
    "reference": "Encounter/ExampleNPCoreEncounter"
  },
  "effectiveDateTime": "2026-05-10T09:10:00+05:45",
  "performer": [
    {
      "reference": "Practitioner/ExampleNPCorePractitioner"
    }
  ],
  "component": [
    {
      "code": {
        "coding": [
          {
            "system": "http://loinc.org",
            "code": "8480-6",
            "display": "Systolic blood pressure"
          }
        ]
      },
      "valueQuantity": {
        "value": 148,
        "unit": "mmHg",
        "system": "http://unitsofmeasure.org",
        "code": "mm[Hg]"
      }
    },
    {
      "code": {
        "coding": [
          {
            "system": "http://loinc.org",
            "code": "8462-4",
            "display": "Diastolic blood pressure"
          }
        ]
      },
      "valueQuantity": {
        "value": 94,
        "unit": "mmHg",
        "system": "http://unitsofmeasure.org",
        "code": "mm[Hg]"
      }
    }
  ]
}

Narrative (text) removed for readability.