M5K

BCBS Prefix M5K

Blue Cross and Blue Shield of Illinois

Illinois • PPO, Medicaid, High-Deductible Health Plan (HDHP)

Billing essentials

Provider phone
(877) 860-2837
Electronic payer ID
00621
Claims mailing address
P.O. Box 650712 Dallas, TX 75265-0712
Timely filing limit
180 daysCompare all plans
Prior authorization phone
(800) 654-7385

Coverage under prefix M5K

PPO

PPO coverage under this prefix means the member can access any provider. In-network providers have negotiated rates with the plan, while out-of-network providers are reimbursed based on usual and customary charges. Prior authorization is generally not required for routine services but may be needed for high-cost procedures.

Medicaid

This prefix is associated with Medicaid managed care. When a BCBS plan administers Medicaid, the claims process may differ from commercial coverage: different payer ID, different claims address, different prior authorization rules, and different timely filing limits. Always verify Medicaid-specific details before submitting.

HDHP

This prefix is associated with a High-Deductible Health Plan. HDHP members pay more out-of-pocket before insurance coverage begins. These plans are commonly paired with HSA or HRA accounts. When billing, be aware that the member may have significant cost-sharing responsibility until their annual deductible is satisfied.

About Blue Cross and Blue Shield of Illinois

State's only statewide customer-owned health insurer and independent licensee of the Blue Cross Blue Shield Association. Serves Illinois with commercial, Medicare, Medicaid and other plans.