Skip to content

LOINC - Laboratory Observations

Logical Observation Identifiers Names and Codes

LOINC is a universal standard for identifying medical laboratory observations. It provides a comprehensive set of codes for laboratory tests, clinical observations, and vital signs.

Overview

  • Full Name: Logical Observation Identifiers Names and Codes
  • Codes: 90,000+ active codes
  • System URL: http://loinc.org
  • Maintained By: Regenstrief Institute
  • Update Frequency: Biannual (June and December)

Key Features

Comprehensive Coverage

LOINC covers: - Laboratory Tests: Chemistry, hematology, microbiology, serology - Clinical Observations: Vital signs, physical findings - Radiology: Imaging studies and reports - Clinical Documents: Discharge summaries, progress notes - Survey Instruments: Standardized questionnaires

Hierarchical Organization

graph TD A[LOINC] --> B[Laboratory] A --> C[Clinical] A --> D[Radiology] A --> E[Documents] B --> F[Chemistry] B --> G[Hematology] B --> H[Microbiology] C --> I[Vital Signs] C --> J[Physical Exam]

Common LOINC Codes

Vital Signs

Code Display Name Units
8867-4 Heart rate beats/min
8480-6 Systolic blood pressure mmHg
8462-4 Diastolic blood pressure mmHg
8310-5 Body temperature °C or °F
9279-1 Respiratory rate breaths/min
2708-6 Oxygen saturation %
29463-7 Body weight kg or lb
8302-2 Body height cm or in
39156-5 Body mass index (BMI) kg/m²

Common Lab Tests

Code Display Name Specimen
2345-7 Glucose Serum/Plasma
2160-0 Creatinine Serum/Plasma
6690-2 White blood cell count Blood
789-8 Erythrocytes Blood
718-7 Hemoglobin Blood
4544-3 Hematocrit Blood
777-3 Platelets Blood
2951-2 Sodium Serum/Plasma
2823-3 Potassium Serum/Plasma

Usage in FHIR

Observation Resource

{
  "resourceType": "Observation",
  "status": "final",
  "category": [{
    "coding": [{
      "system": "http://terminology.hl7.org/CodeSystem/observation-category",
      "code": "vital-signs"
    }]
  }],
  "code": {
    "coding": [{
      "system": "http://loinc.org",
      "code": "8867-4",
      "display": "Heart rate"
    }]
  },
  "subject": {
    "reference": "Patient/123"
  },
  "effectiveDateTime": "2024-11-24T10:00:00Z",
  "valueQuantity": {
    "value": 75,
    "unit": "beats/minute",
    "system": "http://unitsofmeasure.org",
    "code": "/min"
  }
}

Laboratory Result

{
  "resourceType": "Observation",
  "status": "final",
  "category": [{
    "coding": [{
      "system": "http://terminology.hl7.org/CodeSystem/observation-category",
      "code": "laboratory"
    }]
  }],
  "code": {
    "coding": [{
      "system": "http://loinc.org",
      "code": "2345-7",
      "display": "Glucose [Mass/volume] in Serum or Plasma"
    }]
  },
  "subject": {
    "reference": "Patient/123"
  },
  "valueQuantity": {
    "value": 95,
    "unit": "mg/dL",
    "system": "http://unitsofmeasure.org",
    "code": "mg/dL"
  },
  "referenceRange": [{
    "low": {
      "value": 70,
      "unit": "mg/dL"
    },
    "high": {
      "value": 100,
      "unit": "mg/dL"
    }
  }]
}

LOINC Parts

LOINC codes are constructed from six main parts:

graph LR A[Component] --> G[LOINC Code] B[Property] --> G C[Time] --> G D[System] --> G E[Scale] --> G F[Method] --> G

Part Definitions

  1. Component: What is being measured (e.g., Glucose, Hemoglobin)
  2. Property: Type of measurement (e.g., Mass, Volume, Concentration)
  3. Time: When measured (e.g., Point in time, 24 hour)
  4. System: Where measured (e.g., Blood, Serum, Urine)
  5. Scale: How measured (e.g., Quantitative, Ordinal, Nominal)
  6. Method: Technique used (e.g., Automated, Manual)

Searching LOINC

By Code

observation := loinc.LookupCode("8867-4")
// Returns: Heart rate

By Component

codes := loinc.SearchByComponent("glucose")
// Returns: All glucose-related codes

By System

codes := loinc.SearchBySystem("Serum")
// Returns: All serum-based tests

Best Practices

Use Standard Units

Always use UCUM (Unified Code for Units of Measure) units with LOINC codes for consistency.

Version Awareness

LOINC codes can change between versions. Always specify the version in production systems.

Panel Codes

LOINC includes panel codes that group related tests (e.g., Complete Blood Count panel).

Integration with ZarishSphere

The ZarishSphere Platform uses LOINC for: - Vital signs recording - Laboratory test results - Clinical observations - Health assessments

Resources

Next Steps