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Code Systems Reference

Last Updated: 2025-10-17 Version: v0.1.0-alpha Total Systems: 51

This document provides a comprehensive reference of all code systems supported by ccdakit, including their OIDs, descriptions, and usage guidelines.

Overview

ccdakit supports 51 healthcare code systems commonly used in C-CDA documents. These systems are organized into categories and provide automatic OID lookup, format validation, and metadata retrieval through the CodeSystemRegistry utility class.

Quick Reference

Using Code Systems

from ccdakit.builders.common import Code
from ccdakit.utils.code_systems import CodeSystemRegistry

# Create a code using system name (automatic OID lookup)
code = Code(
    code="8867-4",
    system="LOINC",
    display_name="Heart rate"
)

# Get OID for a system
oid = CodeSystemRegistry.get_oid("LOINC")  # Returns "2.16.840.1.113883.6.1"

# Get system name from OID
name = CodeSystemRegistry.get_name("2.16.840.1.113883.6.1")  # Returns "LOINC"

# Validate code format
is_valid = CodeSystemRegistry.validate_code_format("8867-4", "LOINC")  # Returns True

# Get system metadata
info = CodeSystemRegistry.get_system_info("LOINC")
# Returns: {
#     "oid": "2.16.840.1.113883.6.1",
#     "name": "Logical Observation Identifiers Names and Codes",
#     "description": "...",
#     "url": "https://loinc.org",
#     "format_pattern": r"^\d{1,5}-\d$"
# }

# List all systems
systems = CodeSystemRegistry.list_systems()

# Get systems grouped by category
categories = CodeSystemRegistry.get_systems_by_category()

Clinical Terminology Systems

LOINC

  • OID: 2.16.840.1.113883.6.1
  • Full Name: Logical Observation Identifiers Names and Codes
  • Description: International standard for identifying medical laboratory observations
  • URL: https://loinc.org
  • Format: #####-# (e.g., 8867-4)
  • Common Uses: Lab results, vital signs, clinical observations
  • Example: 8867-4 (Heart rate)

SNOMED CT

  • OID: 2.16.840.1.113883.6.96
  • Full Name: Systematized Nomenclature of Medicine Clinical Terms
  • Description: Comprehensive clinical terminology covering diseases, findings, procedures, microorganisms, substances, etc.
  • URL: https://www.snomed.org
  • Format: 6-18 digit numeric code (e.g., 73211009)
  • Common Uses: Problems, diagnoses, procedures, body sites, allergies
  • Example: 73211009 (Diabetes mellitus)

RxNorm

  • OID: 2.16.840.1.113883.6.88
  • Full Name: RxNorm
  • Description: Normalized naming system for generic and branded drugs
  • URL: https://www.nlm.nih.gov/research/umls/rxnorm
  • Format: Numeric (e.g., 197361)
  • Common Uses: Medications, drug products, clinical drugs
  • Example: 197361 (Aspirin 81 MG Oral Tablet)

ICD-10

  • OID: 2.16.840.1.113883.6.90
  • Full Name: International Classification of Diseases, 10th Revision
  • Description: WHO's classification of diseases and health conditions
  • URL: https://www.who.int/classifications/icd
  • Format: Letter followed by 2 digits, optional decimal and 1-4 more digits (e.g., I10, E11.9)
  • Common Uses: Diagnoses, conditions, mortality reporting
  • Example: I10 (Essential hypertension)

ICD-10-CM

  • OID: 2.16.840.1.113883.6.90
  • Full Name: International Classification of Diseases, 10th Revision, Clinical Modification
  • Description: US clinical modification of ICD-10 for morbidity classification
  • URL: https://www.cdc.gov/nchs/icd/icd10cm.htm
  • Format: Same as ICD-10 (e.g., E11.65)
  • Common Uses: Diagnoses in US healthcare settings
  • Example: E11.65 (Type 2 diabetes with hyperglycemia)

ICD-10-PCS

  • OID: 2.16.840.1.113883.6.4
  • Full Name: International Classification of Diseases, 10th Revision, Procedure Coding System
  • Description: US procedural classification for inpatient procedures
  • URL: https://www.cms.gov/Medicare/Coding/ICD10
  • Format: 7 alphanumeric characters (excludes I and O) (e.g., 0W9G30Z)
  • Common Uses: Inpatient procedures
  • Example: 0DT60ZZ (Resection of stomach)

ICD-9-CM

  • OID: 2.16.840.1.113883.6.103
  • Full Name: International Classification of Diseases, 9th Revision, Clinical Modification
  • Description: Legacy diagnosis coding system (replaced by ICD-10-CM in 2015)
  • URL: https://www.cdc.gov/nchs/icd/icd9cm.htm
  • Format: 3-5 characters (e.g., 250.00, V01.0, E800)
  • Common Uses: Historical diagnoses
  • Example: 250.00 (Diabetes mellitus without mention of complication)

ICD-9-PCS

  • OID: 2.16.840.1.113883.6.104
  • Full Name: International Classification of Diseases, 9th Revision, Procedure Coding System
  • Description: Legacy procedure coding system
  • URL: https://www.cms.gov/Medicare/Coding/ICD9ProviderDiagnosticCodes
  • Format: 2-4 digits with optional decimal (e.g., 01.23)
  • Common Uses: Historical procedures
  • Example: 99.04 (Transfusion of packed cells)

CPT

  • OID: 2.16.840.1.113883.6.12
  • Full Name: Current Procedural Terminology
  • Description: Medical procedure coding system maintained by AMA
  • URL: https://www.ama-assn.org/practice-management/cpt
  • Format: 5 digits, optional letter suffix (e.g., 99213, 99213F)
  • Common Uses: Procedures, services, evaluation and management
  • Example: 99213 (Office visit, established patient)

CVX

  • OID: 2.16.840.1.113883.12.292
  • Full Name: CVX - Vaccines Administered
  • Description: CDC code set for vaccines
  • URL: https://www2.cdc.gov/vaccines/iis/iisstandards/vaccines.asp
  • Format: 1-3 digit numeric (e.g., 08, 140)
  • Common Uses: Immunizations
  • Example: 08 (Hepatitis B vaccine)

NDC

  • OID: 2.16.840.1.113883.6.69
  • Full Name: National Drug Code
  • Description: FDA code identifying drug products
  • URL: https://www.fda.gov/drugs/development-approval-process-drugs/national-drug-code-directory
  • Format: Segmented numeric (e.g., 0002-1234-01)
  • Common Uses: Drug identification, pharmacy claims
  • Example: 0002-1234-01 (Specific drug package)

HCPCS

  • OID: 2.16.840.1.113883.6.285
  • Full Name: Healthcare Common Procedure Coding System
  • Description: Codes for medical procedures, supplies, and services
  • URL: https://www.cms.gov/Medicare/Coding/MedHCPCSGenInfo
  • Format: Letter followed by 4 digits (e.g., J1234)
  • Common Uses: DME, drugs, supplies, Level II procedures
  • Example: J1234 (Injection, drug name)

NCI Thesaurus

  • OID: 2.16.840.1.113883.3.26.1.1
  • Full Name: National Cancer Institute Thesaurus
  • Description: Cancer-focused terminology
  • URL: https://ncithesaurus.nci.nih.gov
  • Format: Letter C followed by digits (e.g., C1234)
  • Common Uses: Cancer-related concepts, dose forms
  • Example: C42998 (Tablet)

UNII

  • OID: 2.16.840.1.113883.4.9
  • Full Name: Unique Ingredient Identifier
  • Description: FDA unique identifier for substance ingredients
  • URL: https://www.fda.gov/industry/structured-product-labeling-resources/unique-ingredient-identifier-unii
  • Format: 10 alphanumeric characters (e.g., ABC1234DEF)
  • Common Uses: Drug ingredients, substances
  • Example: R16CO5Y76E (Aspirin)

Units of Measure

UCUM

  • OID: 2.16.840.1.113883.6.8
  • Full Name: Unified Code for Units of Measure
  • Description: Standard for representing units of measure
  • URL: https://ucum.org
  • Format: Variable (e.g., mg, mL, kg/m2)
  • Common Uses: Lab results, vital signs, measurements
  • Example: mg/dL (Milligrams per deciliter)

HL7 Vocabulary Systems

HL7

  • OID: 2.16.840.1.113883.5.1
  • Description: HL7 Vocabulary Domain
  • Common Uses: Base HL7 vocabulary

ActClass

  • OID: 2.16.840.1.113883.5.6
  • Description: HL7 Act Class
  • Common Uses: Categorizing acts (observations, encounters, procedures)
  • Example: OBS (Observation), ENC (Encounter)

ActCode

  • OID: 2.16.840.1.113883.5.4
  • Description: HL7 Act Code
  • Common Uses: Specific act types
  • Example: AMB (Ambulatory)

ActMood

  • OID: 2.16.840.1.113883.5.1001
  • Description: HL7 Act Mood
  • Common Uses: Intent or mode of an act
  • Example: EVN (Event), INT (Intent)

ActStatus

  • OID: 2.16.840.1.113883.5.14
  • Description: HL7 Act Status
  • Common Uses: Status of clinical acts
  • Example: active, completed, aborted

ObservationInterpretation

  • OID: 2.16.840.1.113883.5.83
  • Description: HL7 Observation Interpretation
  • Common Uses: Lab result interpretations
  • Example: H (High), L (Low), N (Normal)

ParticipationType

  • OID: 2.16.840.1.113883.5.90
  • Description: HL7 Participation Type
  • Common Uses: Role of participants in acts
  • Example: AUT (Author), PRF (Performer)

RoleClass

  • OID: 2.16.840.1.113883.5.110
  • Description: HL7 Role Class
  • Common Uses: Categorizing roles
  • Example: PAT (Patient), PROV (Provider)

EntityNameUse

  • OID: 2.16.840.1.113883.5.45
  • Description: HL7 Entity Name Use
  • Common Uses: Purpose of a name
  • Example: L (Legal), C (License), P (Pseudonym)

PostalAddressUse

  • OID: 2.16.840.1.113883.5.1119
  • Description: HL7 Postal Address Use
  • Common Uses: Type of address
  • Example: H (Home), WP (Work Place)

TelecomAddressUse

  • OID: 2.16.840.1.113883.5.1119
  • Description: HL7 Telecom Address Use
  • Common Uses: Type of telecommunication address
  • Example: HP (Primary Home), WP (Work Place)

MaritalStatus

  • OID: 2.16.840.1.113883.5.2
  • Description: HL7 Marital Status
  • Common Uses: Patient marital status
  • Example: M (Married), S (Single)

ReligiousAffiliation

  • OID: 2.16.840.1.113883.5.1076
  • Description: HL7 Religious Affiliation
  • Common Uses: Patient religious affiliation
  • Example: 1001 (Adventist), 1013 (Christian)

AdministrativeGender

  • OID: 2.16.840.1.113883.5.1
  • Description: HL7 Administrative Gender
  • Common Uses: Patient administrative gender
  • Example: M (Male), F (Female), UN (Undifferentiated)

NullFlavor

  • OID: 2.16.840.1.113883.5.1008
  • Description: HL7 Null Flavor
  • Common Uses: Indicating missing or unavailable data
  • Example: UNK (Unknown), NA (Not Applicable), ASKU (Asked but Unknown)

RouteOfAdministration

  • OID: 2.16.840.1.113883.5.112
  • Description: HL7 Route of Administration
  • Common Uses: Medication administration routes
  • Example: PO (Oral), IV (Intravenous)

Confidentiality

  • OID: 2.16.840.1.113883.5.25
  • Description: HL7 Confidentiality
  • Common Uses: Document confidentiality level
  • Example: N (Normal), R (Restricted)

CDC and Demographic Systems

Race

  • OID: 2.16.840.1.113883.6.238
  • Full Name: CDC Race and Ethnicity Code Set
  • Description: CDC standardized race codes
  • URL: https://www.cdc.gov/nchs/data/dvs/Race_Ethnicity_CodeSet.pdf
  • Format: 4 digits, hyphen, 1 digit (e.g., 2054-5)
  • Common Uses: Patient demographics
  • Example: 2054-5 (Black or African American)

Ethnicity

  • OID: 2.16.840.1.113883.6.238
  • Full Name: CDC Race and Ethnicity Code Set
  • Description: CDC standardized ethnicity codes
  • URL: https://www.cdc.gov/nchs/data/dvs/Race_Ethnicity_CodeSet.pdf
  • Format: 4 digits, hyphen, 1 digit (e.g., 2135-2)
  • Common Uses: Patient demographics
  • Example: 2135-2 (Hispanic or Latino)

International Standards

Language

  • OID: 2.16.840.1.113883.6.121
  • Full Name: ISO 639-2 Language Codes
  • Description: International standard for language codes
  • URL: https://www.loc.gov/standards/iso639-2/
  • Format: 3 lowercase letters (e.g., eng)
  • Common Uses: Patient language preferences
  • Example: eng (English), spa (Spanish)

ISO3166

  • OID: 1.0.3166.1.2.2
  • Full Name: ISO 3166 Country Codes
  • Description: International standard for country codes
  • URL: https://www.iso.org/iso-3166-country-codes.html
  • Format: 2 uppercase letters (e.g., US)
  • Common Uses: Country identification in addresses
  • Example: US (United States), CA (Canada)

Healthcare Facility and Billing

NUBC

  • OID: 2.16.840.1.113883.6.301
  • Full Name: National Uniform Billing Committee Revenue Codes
  • Description: Revenue codes for hospital billing
  • URL: https://www.nubc.org
  • Format: 4 digits (e.g., 0450)
  • Common Uses: Hospital billing, revenue reporting
  • Example: 0450 (Emergency room)

DischargeDisposition

  • OID: 2.16.840.1.113883.12.112
  • Full Name: HL7 Discharge Disposition
  • Description: Patient discharge disposition codes
  • URL: https://www.hl7.org/fhir/v2/0112/index.html
  • Format: 2 digits (e.g., 01)
  • Common Uses: Encounter discharge status
  • Example: 01 (Discharged to home)

AdmitSource

  • OID: 2.16.840.1.113883.12.23
  • Full Name: HL7 Admit Source
  • Description: Patient admission source codes
  • URL: https://www.hl7.org/fhir/v2/0023/index.html
  • Format: 1-2 digits (e.g., 7)
  • Common Uses: Encounter admission source
  • Example: 7 (Emergency room)

Clinical Domain Specific

ProcedureCode

  • OID: 2.16.840.1.113883.6.96
  • Description: SNOMED CT codes for procedures
  • Common Uses: Procedures section
  • Example: 80146002 (Appendectomy)

DoseForm

  • OID: 2.16.840.1.113883.3.26.1.1
  • Description: NCI Thesaurus dose form codes
  • Common Uses: Medication dose forms
  • Example: C42998 (Tablet)

BodySite

  • OID: 2.16.840.1.113883.6.96
  • Description: SNOMED CT body site codes
  • Common Uses: Anatomical locations
  • Example: 368209003 (Right arm)

EncounterType

  • OID: 2.16.840.1.113883.5.4
  • Description: HL7 Act Code encounter types
  • Common Uses: Encounter classification
  • Example: AMB (Ambulatory), IMP (Inpatient)

ProblemType

  • OID: 2.16.840.1.113883.3.88.12.3221.7.2
  • Description: HITSP problem type value set
  • Common Uses: Categorizing problems
  • Example: 55607006 (Problem), 404684003 (Finding)

AllergyCategory

  • OID: 2.16.840.1.113883.3.88.12.3221.6.2
  • Description: HITSP allergy category value set
  • Common Uses: Categorizing allergies
  • Example: 416098002 (Drug allergy), 414285001 (Food allergy)

AllergySeverity

  • OID: 2.16.840.1.113883.6.96
  • Description: SNOMED CT allergy severity codes
  • Common Uses: Allergy severity
  • Example: 255604002 (Mild), 6736007 (Moderate), 24484000 (Severe)

ReactionSeverity

  • OID: 2.16.840.1.113883.6.96
  • Description: SNOMED CT reaction severity codes
  • Common Uses: Allergic reaction severity
  • Example: 255604002 (Mild)

MedicationStatus

  • OID: 2.16.840.1.113883.3.88.12.80.20
  • Description: HITSP medication status value set
  • Common Uses: Medication status
  • Example: 55561003 (Active), 73425007 (Inactive)

VitalSignResult

  • OID: 2.16.840.1.113883.6.1
  • Description: LOINC vital sign result codes
  • Common Uses: Vital signs observations
  • Example: 8867-4 (Heart rate), 8480-6 (Systolic blood pressure)

LabResultStatus

  • OID: 2.16.840.1.113883.5.14
  • Description: HL7 Act Status for lab results
  • Common Uses: Lab result status
  • Example: completed, active, aborted

ResultInterpretation

  • OID: 2.16.840.1.113883.5.83
  • Description: HL7 Observation Interpretation for results
  • Common Uses: Lab result interpretation flags
  • Example: H (High), L (Low), N (Normal)

SpecimenType

  • OID: 2.16.840.1.113883.6.96
  • Description: SNOMED CT specimen type codes
  • Common Uses: Laboratory specimens
  • Example: 119297000 (Blood specimen)

Code System Statistics

Category Count
Clinical terminology systems 14
Units of measure 1
HL7 vocabulary systems 18
CDC and demographic systems 2
International standards 2
Healthcare facility and billing 3
Clinical domain specific 14
Total 54

Note: Some systems appear in multiple categories due to overlapping OIDs or usage contexts.

Format Validation

ccdakit provides automatic format validation for many code systems. Systems with defined format patterns will validate codes according to their specification:

from ccdakit.utils.code_systems import CodeSystemRegistry

# Valid LOINC code
CodeSystemRegistry.validate_code_format("8867-4", "LOINC")  # True

# Invalid LOINC code (missing check digit)
CodeSystemRegistry.validate_code_format("8867", "LOINC")  # False

# Valid ICD-10 code
CodeSystemRegistry.validate_code_format("I10", "ICD-10")  # True

# Invalid ICD-10 code (wrong format)
CodeSystemRegistry.validate_code_format("123", "ICD-10")  # False

Systems without defined format patterns (primarily HL7 vocabulary systems) will accept any code value.

Integration with Code Builder

The Code builder class automatically looks up OIDs from system names:

from ccdakit.builders.common import Code

# Using system name - OID is looked up automatically
code = Code(
    code="8867-4",
    system="LOINC",  # Automatically converts to OID 2.16.840.1.113883.6.1
    display_name="Heart rate"
)

# Using OID directly (also supported)
code = Code(
    code="8867-4",
    system="2.16.840.1.113883.6.1",
    display_name="Heart rate"
)

Migration from Previous Versions

v0.1.0-alpha to Current

Previous version supported 9 code systems. This update adds 42 additional systems:

New Systems Added: - ICD-10-PCS, ICD-9-CM, ICD-9-PCS (Legacy coding) - NDC, HCPCS (Drug and procedure coding) - NCI Thesaurus, UNII (Substance identification) - 15 additional HL7 vocabulary systems - Race, Ethnicity (CDC demographics) - Language, ISO3166 (International standards) - NUBC, DischargeDisposition, AdmitSource (Facility and billing) - 14 clinical domain-specific systems

Breaking Changes: None. All existing code systems remain supported with the same OIDs.

Additional Resources

Contributing

To add a new code system:

  1. Add entry to SYSTEMS dict in ccdakit/utils/code_systems.py
  2. Add entry to SYSTEM_OIDS dict in ccdakit/builders/common.py
  3. Add format validation pattern (if applicable)
  4. Add test cases in tests/test_utils/test_code_systems.py
  5. Update this documentation
  6. Add to appropriate category in get_systems_by_category()

Maintained by: ccdakit Development Team Questions?: See CONTRIBUTING.md