## Overview of Common Code Systems The following table shows the most commonly used code system for each clinical application area: | Clinical Application | Primary Code System | CodeSystem URL | Description | Full System Valueset | | --- | --- | --- | --- | --- | | Clinical Findings | LOINC | `http://loinc.org` | Laboratory tests, vital signs, clinical observations | `http://loinc.org/vs` | | Medications | RXNorm | `http://www.nlm.nih.gov/research/umls/rxnorm` | Normalized medication names | `http://www.nlm.nih.gov/research/umls/rxnorm/vs` | | Procedures | CPT | `http://www.ama-assn.org/go/cpt` | Current Procedural Terminology | `http://www.ama-assn.org/go/cpt/vs` | | Diagnoses | ICD-10-CM | `http://hl7.org/fhir/sid/icd-10-cm` | International Classification of Diseases, Clinical Modification | `http://hl7.org/fhir/sid/icd-10-cm/vs` | | Vaccines | CVX | `http://hl7.org/fhir/sid/cvx` | Vaccine Administered | `http://hl7.org/fhir/sid/cvx/vs` | | Allergies (food + environmental) | SNOMED CT | `http://snomed.info/sct` | Substance and clinical concepts | `http://snomed.info/sct/vs` | ## Use-case Specific ValueSets Each clinical area has predefined sets of codes that cover the most common scenarios you'll encounter. While each clinical area has a primary code system, healthcare applications often need to support multiple coding systems for different use cases. ### Clinical Findings and Laboratory Tests | Valueset Name | Description | Valueset URL | Example Values | Code Systems | | --- | --- | --- | --- | --- | | Vital Signs Type | Codes for types of vital sign measurements and clinical observations | `http://hl7.org/fhir/us/core/ValueSet/us-core-vital-signs` | `[8302-2] Body height`, `[8867-4] Heart rate` | LOINC | | Smoking Status | Codes for patient smoking status and tobacco use | `http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.11.20.9.38` | `[8517006] Ex-smoker` | SNOMED CT | | Pregnancy Status | Codes for pregnancy status and related observations | `http://hl7.org/fhir/us/core/ValueSet/us-core-pregnancy-status` | `[77386006] Pregnancy` | SNOMED CT | | SDOH Assessment | Social determinants of health assessment codes | `http://hl7.org/fhir/us/core/ValueSet/us-core-common-sdoh-assessments` | `[71802-3] Housing status` | LOINC | | Sexual Orientation | Codes for sexual orientation and gender identity | `http://hl7.org/fhir/us/core/ValueSet/us-core-sexual-orientation` | `[20430005] Heterosexual` | SNOMED CT | ### Allergies and Adverse Reactions Allergy coding uses SNOMED CT for substance identification and RXNorm for medication allergies, following US Core 5.0.1 specifications. | Code System | System URL | Description | Use Cases | | --- | --- | --- | --- | | SNOMED CT | `http://snomed.info/sct` | Substance and clinical concepts | Food allergies, environmental allergies, clinical findings | | RXNorm | `http://www.nlm.nih.gov/research/umls/rxnorm` | Medication substances | Drug allergies, medication intolerances | **Common ValueSets** | Valueset Name | Description | Valueset URL | Example Values | Code Systems | | --- | --- | --- | --- | --- | | US Core Allergy Substance | Common substances for allergy and intolerance documentation including refutations | `http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113762.1.4.1186.8` | `[7980] Penicillin G` | SNOMED CT, RXNorm | ### Medications For detailed information about medication coding systems including RxNorm and NDC, see [Medication Code Systems](/content/docs/medications/medication-codes/index.html). ### Medical Procedures Procedure coding varies by setting and purpose, with CPT being primary for billing. | Code System | System URL | Description | Use Cases | | --- | --- | --- | --- | | CPT | `http://www.ama-assn.org/go/cpt` | Current Procedural Terminology | Billing, procedure documentation | | HCPCS | `https://www.cms.gov/Medicare/Coding/HCPCSReleaseCodeSets` | Healthcare Common Procedure Coding System | Medicare/Medicaid billing, Value-based care, DME | | SNOMED CT | `http://snomed.info/sct` | Clinical procedure concepts | Clinical documentation, procedure notes | | ICD-10-PCS | `http://www.cms.gov/Medicare/Coding/ICD10` | ICD-10 Procedure Coding System | Hospital inpatient billing | ### Diagnoses and Conditions Diagnosis coding primarily uses ICD-10-CM for standardized disease classification, with SNOMED CT providing more granular clinical concepts preferred in international settings. | Code System | System URL | Description | Use Cases | | --- | --- | --- | --- | | ICD-10-CM | `http://hl7.org/fhir/sid/icd-10-cm` | International Classification of Diseases, Clinical Modification | Primary diagnoses, billing, epidemiology | | SNOMED CT | `http://snomed.info/sct` | Clinical findings and disorders | Clinical documentation, problem lists | ### Vaccines and Immunizations Vaccine coding uses CVX codes for vaccine types and CPT codes for administration procedures. | Code System | System URL | Description | Use Cases | | --- | --- | --- | --- | | CVX | `http://hl7.org/fhir/sid/cvx` | Vaccine Administered | Immunization records, vaccine administration | | CPT | `http://www.ama-assn.org/go/cpt` | Vaccine administration procedures | Billing for vaccine administration | - [Overview of Common Code Systems](/content/docs/terminology/common-terminologies#overview-of-common-code-systems/index.html) - [Use-case Specific ValueSets](/content/docs/terminology/common-terminologies#use-case-specific-valuesets/index.html) - [Clinical Findings and Laboratory Tests](/content/docs/terminology/common-terminologies#clinical-findings-and-laboratory-tests/index.html) - [Allergies and Adverse Reactions](/content/docs/terminology/common-terminologies#allergies-and-adverse-reactions/index.html) - [Medications](/content/docs/terminology/common-terminologies#medications/index.html) - [Medical Procedures](/content/docs/terminology/common-terminologies#medical-procedures/index.html) - [Diagnoses and Conditions](/content/docs/terminology/common-terminologies#diagnoses-and-conditions/index.html) - [Vaccines and Immunizations](/content/docs/terminology/common-terminologies#vaccines-and-immunizations/index.html)