> ## Documentation Index > Fetch the complete documentation index at: https://docs.rcintell.com/llms.txt > Use this file to discover all available pages before exploring further. # NCCI PTP counterparts and MUE units/day for one CPT > What can / cannot be billed with this code. PTP pairs from posted NCCI. MUE is max units **per day**, not yearly utilization. ``frequency`` stays null unless a policy posts it. ## OpenAPI ````yaml /docs/openapi.client.json get /v1/codes/{code}/companions openapi: 3.1.0 info: description: >- Client API for RCIntel. Authenticate with X-API-Key. See Guides → Which API to use. summary: Multi-tenant knowledge API for healthcare revenue cycle management. title: Healthcare Knowledge Layer version: 0.1.0 servers: [] security: [] tags: - description: >- Cited payer policy lookup — GET /v1/policies and GET /v1/policies/changes. Medicare FFS returns NCDs/LCDs/MACs; commercial payers return that payer's documents only. Query payer, code, state, plan_type. name: policies - description: >- Payer-policy PDF parse and retrieve for Workspace / Payer Knowledge. Service-authenticated (X-Admin-Secret); chunks stored in Postgres. name: policy - description: >- Manufacturer 340B contract-pharmacy policy, fail-closed access, and the change feed. Different API from GET /v1/policies. name: 340B Policy - description: CRD-style prior authorization check, documentation, and vendors. name: prior-auth - description: Public payer directory (no API key on list/detail). name: payers-public - description: >- Payer network directory — search payers, check prior auth requirements, view filing rules, denial patterns, and appeal levels. name: payers - description: >- Resolve healthcare billing knowledge across the L1-L6 layer stack. Includes payment calculation, billing guidance, and per-layer queries. name: knowledge - description: >- CMS Fee Schedule lookups — OPPS (Addendum B / APC), DMEPOS (state-level pricing), and Clinical Lab Fee Schedule (CLFS). name: fee-schedules - description: >- NCCI (National Correct Coding Initiative) — dedicated MUE limits, PTP bundling edits, add-on code edits, and code pair validation. Medicare edits under /ncci/*, the separate CMS Medicaid edit set under /ncci/medicaid/*. name: ncci - description: >- Service code intelligence — CPT/HCPCS lookup, RVU data, NCCI edits, payment calculation, implant/GUDID search, and service group classification. name: codes - description: >- Submit asynchronous AI agent jobs for code research, medical necessity, and denial resolution. Poll for results and retrieve reasoning traces. name: agents - description: >- Register and manage healthcare facilities by CCN (Medicare Provider Number). Each facility is the root entity for knowledge resolution. name: facilities - description: >- NPI Registry — live search against CMS NPPES API for provider and organization National Provider Identifiers. name: npi - description: >- OpenFDA drug product lookup by NDC. Includes product-level fields with normalized ingredient and package detail. name: drugs - name: encounter - name: mcp - description: Health checks, service metadata, and Prometheus metrics. name: system paths: /v1/codes/{code}/companions: get: tags: - codes summary: NCCI PTP counterparts and MUE units/day for one CPT description: |- What can / cannot be billed with this code. PTP pairs from posted NCCI. MUE is max units **per day**, not yearly utilization. ``frequency`` stays null unless a policy posts it. operationId: get_code_companions_v1_codes__code__companions_get parameters: - description: >- Billing or terminology code value (CPT/HCPCS/NDC/etc depending on endpoint context). in: path name: code required: true schema: title: Code type: string responses: '200': content: application/json: schema: $ref: '#/components/schemas/CodeCompanionsResponse' description: Successful Response '422': content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' description: Validation Error security: - APIKeyHeader: [] components: schemas: CodeCompanionsResponse: properties: code: title: Code type: string companions: items: $ref: '#/components/schemas/CompanionCode' title: Companions type: array frequency: anyOf: - additionalProperties: true type: object - type: 'null' description: Posted policy frequency only. Null unless a document states it. title: Frequency units: items: $ref: '#/components/schemas/CompanionUnits' title: Units type: array required: - code title: CodeCompanionsResponse type: object HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' title: Detail type: array title: HTTPValidationError type: object CompanionCode: description: One NCCI PTP counterpart. Not claims co-occurrence. properties: bill_together: description: do_not_bill_together | modifier_may_bypass | not_applicable title: Bill Together type: string claim_type: anyOf: - type: string - type: 'null' title: Claim Type column: description: 1 if this code is column 1, else 2 title: Column type: integer counterpart_code: title: Counterpart Code type: string modifier_allowed: title: Modifier Allowed type: boolean modifier_indicator: anyOf: - type: string - type: 'null' title: Modifier Indicator rationale: anyOf: - type: string - type: 'null' title: Rationale required: - counterpart_code - column - modifier_allowed - bill_together title: CompanionCode type: object CompanionUnits: description: MUE max units per day for the requested code. properties: adjudication: anyOf: - type: string - type: 'null' title: Adjudication mue_per_day: title: Mue Per Day type: integer period: default: day title: Period type: string setting: title: Setting type: string source: default: cms_ncci_mue title: Source type: string required: - mue_per_day - setting title: CompanionUnits type: object ValidationError: properties: ctx: title: Context type: object input: title: Input loc: items: anyOf: - type: string - type: integer title: Location type: array msg: title: Message type: string type: title: Error Type type: string required: - loc - msg - type title: ValidationError type: object securitySchemes: APIKeyHeader: in: header name: X-API-Key type: apiKey ````