Patientary

Validation tool

Check any NPI or ICD-10 code before you file it

Paste NPI numbers and ICD-10-CM codes below to check them in one pass — structural validity for NPIs, and existence plus billable status for ICD-10 codes.

One per line or comma-separated.

One per line or comma-separated.

Single-item checks are free and unlimited here. Submitting more than one item at once uses the batch endpoint, which requires an API key on a paid plan — see pricing.

How it works

Two different checks, one tool

An NPI check is offline and instant. An ICD-10 check confirms the code is real, not just well-formed.

NPI: the Luhn check digit

An NPI is a 10-digit number whose last digit is a checksum computed over the first nine digits (prefixed with the constant issuer code CMS assigns to NPIs), using the same Luhn algorithm credit card numbers use. That means Patientary can tell you instantly, with no network call, whether a number is structurallya valid NPI — though only the live registry confirms it’s actually assigned to a provider (see NPI lookup).

ICD-10: format and existence

An ICD-10-CM code has a fixed shape — a letter, two alphanumeric characters, then an optional dot and up to four more. Patientary checks that shape first, then looks the code up against the current official CMS ICD-10-CM release to confirm it actually exists and whether it’s billable, so a well-formed but retired or invented code is still flagged.

For developers

Scrub a claim in one API call

Send a mix of NPIs and ICD-10 codes and get back a valid/invalid verdict with a reason for each — the exact check this page runs, callable from your billing pipeline or an AI agent.

See the full API reference

patientary api

$ curl -X POST patientary.com/api/v1/validate \
  -d '{"npis":["1245319599"],"icd10":["E11.9","Z999"]}'

{
  "count": 2,
  "valid": 1,
  "results": [
    { "type": "npi", "npi": "1245319599", "valid": true },
    { "type": "icd10", "code": "Z999", "valid": false,
      "reason": "Well-formed, but not a code in the
                 current ICD-10-CM release." }
  ]
}

Patientary is an informational reference tool built on public data (CMS NPPES and the official ICD-10-CM release). It is not medical, coding, legal or billing advice, and code assignment is the responsibility of a qualified professional. Always verify against the primary source before you bill or file.