1. Is the number valid?
An NPI has 10 digits and starts with 1 or 2. The last digit is a check digit calculated with the Luhn formula (the same one used for credit cards, with the prefix 80840 in front). A number that fails the check was never issued. Our lookup runs this test first, so a typo shows up right away.
2. Is it active?
A valid NPI can still be deactivated, for example after a provider dies or a business closes. Deactivated NPIs disappear from the NPPES registry without explanation. We compare every number with the CMS deactivated NPI report and show the date it was deactivated.
3. Does it match the provider?
Check that the name, entity type and primary taxonomy code on the NPI record match what you have. For claims, the taxonomy code you bill with should be one of the codes on the record. For credentialing, compare the license number and state on the NPI with the state board's own lookup, because NPPES shows what the provider reported, not what the board confirmed.
Verifying many NPIs
Billing companies, pharmacies and credentialing teams usually need to verify a roster, not one person. The bulk NPI verification tool runs all three checks on up to 5,000 NPIs and gives you a spreadsheet you can sort by status.