STO

BCBS Prefix STO

Blue Cross and Blue Shield of Massachusetts

Massachusetts • Medicaid, HMO, High-Deductible Health Plan (HDHP)

Billing essentials

Provider phone
(800) 443-6657
Electronic payer ID
00200
Claims mailing address
P.O. Box 986030, Boston MA 02298
Timely filing limit
180 daysCompare all plans
Prior authorization phone
(800) 443-6657

Coverage under prefix STO

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.

HMO

HMO coverage means this member must use providers within the plan's network. A primary care physician serves as the care coordinator and must authorize specialist referrals. Emergency services are the primary exception to the network requirement. Always verify referral status before providing non-emergency specialty care.

HDHP

HDHP (High-Deductible Health Plan) coverage means the member has a higher deductible than traditional plans, often paired with a Health Savings Account (HSA). Most services require the member to pay out-of-pocket until the deductible is met. Preventive care is typically covered before the deductible. Submit claims normally to the payer listed above.

About Blue Cross and Blue Shield of Massachusetts

Independent licensee serving Massachusetts members with commercial, Medicare and Medicaid plans.