The IL Medicaid payer ID is IL621.
Illinois Medicaid 837P Companion Guide
To review Illinois Medicaid 837P electronic submission requirements, refer to the official companion guide:
https://hfs.illinois.gov/content/dam/soi/en/web/hfs/sitecollectiondocuments/837p.pdf
This guide outlines the standards and payer-specific rules for submitting professional (837P) claims to Illinois Medicaid.
Secondary Claim Submission
When sending secondary claims to IL Medicaid (Payer ID IL621), use the appropriate unique identifier to ensure accurate claim submission and processing. This helps streamline reimbursements and maintain compliance with Illinois Medicaid billing requirements.
For electronic (837P) claims, this value is submitted in:
Loop 2330B, REF02 (Other Payer Secondary Identifier)For paper (CMS-1500) claims, this value is submitted in:
Box 9d
Note:
Box 9d applies only to paper claims. For electronic submissions, this information must be sent in Loop 2330B, REF02 as outlined above.
The value is made up of:
A 3-digit TPL (payer) code
A 2-digit status code
These must be entered in this order:
Payer code first
Status code second
Example
91001
910 = Medicare Part B (primary payer)
01 = TPL adjudicated (payment information included)
Important
The order matters — payer code must come before the status code
Reversing the order will result in claim rejections
Do not include spaces, dashes, or separators
Enter the value as one continuous number
Additional Notes
This applies when another insurance payer has processed the claim before Illinois Medicaid
TPL (Third Party Liability) codes and status codes are maintained by Illinois Medicaid (HFS)
Always verify that both codes are current and valid