MedicaidAdministrativeHigh impact
National Provider Identifier (NPI) – Prescriber ID and Primary Care Provider ID
Illinois Medicaid - HFS·IL · Pharmacy·Provider Notice
Effective date
Sep 15, 2010
We identified it
Jun 21, 2026
Summary
Effective September 15, 2010, pharmacies must use National Provider Identifier (NPI) numbers instead of DEA, License, or Legacy ID numbers in both Prescriber ID and Primary Care Provider ID fields for all electronic and paper claims. Claims without proper NPIs will be rejected with specific error codes.
Action Required
By September 15, 2010: All pharmacies must update billing systems to require NPI numbers in Prescriber ID field (411-DB) and Primary Care Provider ID field (421-DL) for all claims. Stop using DEA numbers, License numbers, or HFS Legacy ID numbers. Update paper adjustment forms to include NPI in Provider Number field. Claims without proper NPIs will be rejected with error codes EZ, 25, 2E, or 35.