LabTest

Reference data for laboratory tests with standardized coding (LOINC). Defines test specifications including categories, specimen requirements, units of measurement, and normal/critical reference ranges.

Overview

LabTest provides the reference catalog of diagnostic laboratory tests available for ordering. Each test is coded using LOINC (Logical Observation Identifiers Names and Codes), with details about specimen requirements, measurement units, and reference ranges. This reference data supports test ordering, result interpretation, and clinical decision support by providing standardized test definitions.

Key Concepts

LOINC Coding

The primary coding system for laboratory tests:

  • code - LOINC code (e.g., "2345-7" for glucose)
  • system - Coding system (LOINC, SNOMED-CT)
  • label - Full LOINC long name
  • shortName - Display name for UI

Test Categories

The category field classifies tests by laboratory section:

CategoryDescriptionExamples
chemistryClinical chemistryGlucose, electrolytes, liver enzymes
hematologyBlood cell analysisCBC, coagulation studies
microbiologyInfectious diseaseCultures, sensitivities
urinalysisUrine analysisUA, microscopy
immunologyImmune systemAntibodies, autoimmune markers
pathologyTissue analysisBiopsies, cytology
geneticsDNA/RNA testingGenetic markers, mutations
toxicologyDrug and poison testingDrug screens, levels

Specimen Requirements

The specimenType field specifies collection needs:

  • Blood (venous, arterial, capillary)
  • Serum or Plasma
  • Urine (random, 24-hour, clean catch)
  • CSF (cerebrospinal fluid)
  • Tissue (biopsy, aspirate)
  • Swabs (throat, wound, nasal)

Units of Measurement

The unit field defines result units:

  • mg/dL, g/dL - mass concentrations
  • mEq/L, mmol/L - molar concentrations
  • cells/uL - cell counts
  • %, ratio - proportions
  • IU/L - enzyme activity

Reference Ranges

Normal value boundaries:

  • referenceRangeLow - Lower normal limit
  • referenceRangeHigh - Upper normal limit
  • May vary by age, sex, pregnancy status
  • Provides baseline for interpretation

Critical Values

Life-threatening thresholds:

  • criticalLow - Dangerously low value
  • criticalHigh - Dangerously high value
  • Require immediate provider notification
  • Defined per laboratory policy

Use Cases

Test Catalog Management

Building laboratory menu:

  1. Import tests from LOINC database
  2. Assign to laboratory sections
  3. Define specimen requirements
  4. Set reference ranges
  5. Configure critical thresholds

Order Entry

When ordering tests:

  1. Search by name or code
  2. Display specimen requirements
  3. Show expected turnaround time
  4. Group into common panels
  5. Apply ordering rules

Result Interpretation

When reviewing results:

  1. Compare value to reference range
  2. Flag abnormal results
  3. Alert on critical values
  4. Display with appropriate units
  5. Support trend analysis

Quality Control

For laboratory compliance:

  1. Verify reference ranges
  2. Update critical thresholds
  3. Track test utilization
  4. Monitor turnaround times
  5. Maintain LOINC mappings

Clinical Decision Support

For CDS rules:

  1. Define alerting logic by test
  2. Set therapeutic ranges
  3. Configure reflex testing
  4. Support result-based protocols
  5. Enable population health queries

Related Entities

EntityRelationshipDescription
LaboratoryOrderReferenced byOrders for this test
LaboratoryResultReferenced byResults of this test
SpecimenReferenced bySpecimens required

Enums

system

ValueDescription
LOINCLogical Observation Identifiers Names and Codes - primary lab test terminology
SNOMED-CTSystematized Nomenclature of Medicine for clinical findings
otherOther coding system not listed

category

ValueDescription
chemistryClinical chemistry including metabolic panels, liver function, cardiac markers
hematologyBlood cell analysis including CBC, differential, coagulation studies
microbiologyInfectious disease testing including cultures, sensitivities, molecular detection
urinalysisUrine testing including dipstick, microscopy, and chemistry
immunologyImmune system testing including antibodies, autoimmune markers, allergies
pathologyTissue and cytology analysis including biopsies and surgical specimens
geneticsDNA and RNA testing including genetic markers and mutations
toxicologyDrug and toxin testing including screens, levels, and confirmatory tests
otherOther laboratory category not listed
12 properties
Schema

Properties

PropertyTypeModeDescriptionRequired
codestring
stored

LOINC code for the test

Example: "2345-7"

Required
systemstring
stored

Coding system used

Values: LOINC, SNOMED-CT, other

Example: "LOINC"

Required
labelstring
stored

Human-readable name of the test

Example: "Glucose [Mass/volume] in Serum or Plasma"

Required
shortNamestring
stored

Short display name

Example: "Glucose"

Optional
categorystring
stored

Category of laboratory test

Values: chemistry, hematology, microbiology, urinalysis, immunology, pathology, genetics, toxicology, other

Example: "chemistry"

Optional
specimenTypestring
stored

Type of specimen required

Example: "Blood"

Optional
unitstring
stored

Standard unit of measurement

Example: "mg/dL"

Optional
referenceRangeLownumber
stored

Standard lower reference range bound

Example: 70

Optional
referenceRangeHighnumber
stored

Standard upper reference range bound

Example: 100

Optional
criticalLownumber
stored

Critical low value threshold

Example: 40

Optional
criticalHighnumber
stored

Critical high value threshold

Example: 500

Optional
descriptionstring
stored

Additional details about the test

Optional

Examples

Example 1

{
  "@type": "LabTest",
  "code": "2345-7",
  "system": "LOINC",
  "label": "Glucose [Mass/volume] in Serum or Plasma",
  "shortName": "Glucose",
  "category": "chemistry",
  "specimenType": "Blood",
  "unit": "mg/dL",
  "referenceRangeLow": 70,
  "referenceRangeHigh": 100,
  "criticalLow": 40,
  "criticalHigh": 500
}

Example 2

{
  "@type": "LabTest",
  "code": "2823-3",
  "system": "LOINC",
  "label": "Potassium [Moles/volume] in Serum or Plasma",
  "shortName": "Potassium",
  "category": "chemistry",
  "specimenType": "Blood",
  "unit": "mEq/L",
  "referenceRangeLow": 3.5,
  "referenceRangeHigh": 5,
  "criticalLow": 2.5,
  "criticalHigh": 6.5
}

Example 3

{
  "@type": "LabTest",
  "code": "718-7",
  "system": "LOINC",
  "label": "Hemoglobin [Mass/volume] in Blood",
  "shortName": "Hemoglobin",
  "category": "hematology",
  "specimenType": "Blood",
  "unit": "g/dL",
  "referenceRangeLow": 12,
  "referenceRangeHigh": 17.5,
  "criticalLow": 7,
  "criticalHigh": 20
}