MedicaidBilling CodesMedium impact
Use of Modifier 90 - March 1, 2018
Illinois Medicaid - HFS·IL · Pathology·Provider Notice
Effective date
Mar 1, 2018
We identified it
Jun 20, 2026
Summary
Effective March 1, 2018, hospitals must add modifier 90 to all outpatient lab services performed by reference (outside) laboratories when billing fee-for-service claims. This allows the Department to track services and prevent duplicate payments.
Action Required
By March 1, 2018: Billing team must update system to automatically append modifier 90 to all outpatient lab procedure codes when services are performed by reference laboratories. Verify all reference laboratories are enrolled with the Department. Update billing software rules to prevent submission of claims without modifier 90 for outside lab work.