Patient Control Number (PCN)

The Patient Control Number (PCN) is a unique identifier generated for each Claim resource. It is the primary key used to match an incoming ClaimResponse (from an 835 ERA or 277 file) back to the original claim.

Where it lives

The PCN is stored in the Claim.identifier array:

{
  "resourceType": "Claim",
  "identifier": [
    {
      "system": "http://aidbox.billing.com/CodeSystem/patient-control-number",
      "value": "PCN-a1b2c3d4"
    }
  ]
}

When it is generated

The build-draft-claim activity generates the PCN at claim creation time and embeds it in the Claim. The PCN is preserved through all subsequent status changes (draft → active → response matched).

How matching works

When an 835 ERA file is processed:

1. parse-x12 reads the raw EDI.
2. map-835-to-claim-responses creates draft ClaimResponse resources. The PCN from the ERA's CLP segment is extracted into each ClaimResponse.identifier.
3. The link-claim-response workflow searches for a Claim whose PCN matches the ClaimResponse's PCN.
4. If found: link-claim-response links the ClaimResponse to the Claim — match status: matched.
5. If not found: fuzzy matching by member ID is attempted; if that also fails, the ClaimResponse is marked unmatched.

Match statuses

ClaimResponse resources carry a match-status extension:

Why PCN matters

Without a PCN, ERA matching relies entirely on fuzzy member ID matching, which is error-prone when a patient has multiple claims at a payer. PCN-based matching is exact and unambiguous. Clearinghouses pass the PCN back in the 835's CLP segment verbatim, making end-to-end claim tracking reliable.

See also