Code systems

When working with coded medical data, code systems allow implementers to interpret a coded value in the context of the system which defined it. This is helpful for interoperability since it enables different applications to speak a common language.

However code systems are not referenced consistently across payers. This poses a challenge to implementers who expect, for example, to reference the official URI for the ICD-10 code system http://hl7.org/fhir/sid/icd-10 but instead receive https://icd.who.int/browse10/2019/en in a payload.

Flexpa's API maps non-standardized versions of code system URIs to standardized versions, so that developers can know what to expect in FHIR payloads. This reference documents the code system URIs which developers can expect to appear in FHIR resources that are returned by Flexpa's API.

Please note that Flexpa's system URI map is constantly expanding and improving. If you come across a code system URI that you would like to be standardized, please let us know at support@flexpa.com.

Legend

HL7 lists several types of code systems. They can be categorized as:

```
Code system
```
A system that is defined by HL7 FHIR
```
Naming system
```
A curated namespace that is often used for the identification of concepts, people, devices, etc.
```
External code system
```
A system that is defined by an organization that is external to, but referenced by, HL7. See HL7 External code systems
```
FHIR resource
```
A system that references the definition of a FHIR resource

Supported code systems

Flexpa's API attempts to map the following code systems in place within FHIR resource payloads. The mapped value is set to the system URI.

Name	URI	Other IDs
AdjudicationValueCodes	http://terminology.hl7.org/CodeSystem/adjudication	urn:oid:2.16.840.1.113883.4.642.1.1171
IdentifierType	http://terminology.hl7.org/CodeSystem/v2-0203	urn:oid:2.16.840.1.113883.18.108
ClaimInformationCategoryCodes	http://terminology.hl7.org/CodeSystem/claiminformationcategory	urn:oid:2.16.840.1.113883.4.642.1.1163
C4BBSupportingInfoType	http://hl7.org/fhir/us/carin-bb/CodeSystem/C4BBSupportingInfoType
C4BBPayerAdjudicationStatus	http://hl7.org/fhir/us/carin-bb/CodeSystem/C4BBPayerAdjudicationStatus
USEIN	http://terminology.hl7.org/NamingSystem/USEIN	urn:oid:2.16.840.1.113883.4.4
CDCREC	http://terminology.hl7.org/NamingSystem/CDCREC	urn:oid:2.16.840.1.113883.6.238
SNOMED	http://snomed.info/sct	urn:oid:2.16.840.1.113883.6.96
RxNorm	http://www.nlm.nih.gov/research/umls/rxnorm	urn:oid:2.16.840.1.113883.6.88
LOINC	http://loinc.org	urn:oid:2.16.840.1.113883.6.1
pCLOCD	https://fhir.infoway-inforoute.ca/CodeSystem/pCLOCD	urn:oid:2.16.840.1.113883.2.20.5.1
UCUM	http://unitsofmeasure.org	urn:oid:2.16.840.1.113883.6.8
CPT	http://www.ama-assn.org/go/cpt	urn:oid:2.16.840.1.113883.6.12
MED-RT	http://va.gov/terminology/medrt	urn:oid:2.16.840.1.113883.6.345
NDF-RT	http://hl7.org/fhir/ndfrt	urn:oid:2.16.840.1.113883.6.209
UNII	http://fdasis.nlm.nih.gov	urn:oid:2.16.840.1.113883.4.9
NDC	http://hl7.org/fhir/sid/ndc	urn:oid:2.16.840.1.113883.6.69
CVX	http://hl7.org/fhir/sid/cvx	urn:oid:2.16.840.1.113883.12.292
ICD-10	http://hl7.org/fhir/sid/icd-10	urn:oid:2.16.840.1.113883.6.3
ICD-10-CM	http://hl7.org/fhir/sid/icd-10-cm	urn:oid:2.16.840.1.113883.6.90
ICD-9	http://terminology.hl7.org/CodeSystem/icd9	urn:oid:2.16.840.1.113883.6.42
ICD-9-CM	http://terminology.hl7.org/CodeSystem/icd9cm	urn:oid:2.16.840.1.113883.6.2
MDC	urn:iso:std:iso:11073:10101	urn:oid:2.16.840.1.113883.6.24
HCPCS	https://www.cms.gov/Medicare/Coding/HCPCSReleaseCodeSets	urn:oid:2.16.840.1.113883.6.285
UPC	http://terminology.hl7.org/CodeSystem/UPC	urn:oid:2.16.840.1.113883.6.55
CDT	http://www.ada.org/cdt	urn:oid:2.16.840.1.113883.6.13
USPS	https://www.usps.com
Patient	https://www.hl7.org/fhir/patient.html
ExplanationOfBenefit	https://www.hl7.org/fhir/explanationofbenefit.html
Total 29

Note: If you require a specific code system to be supported, contact support@flexpa.com.