Ancillary services
Updated September 30, 2026
Definition
Care that supports your main treatment, like anesthesia, lab tests, imaging, and pathology. At an in-network facility, these providers can't ask you to give up your surprise billing protections.
Ancillary services are the care that supports your main treatment. Think of the doctor who puts you to sleep for surgery, the lab that tests your blood, or the doctor who reads your scan. You often don't pick these providers. You may never meet them.
They matter because they often send their own bills. Under the No Surprises Act, this group covers emergency doctors, anesthesia, lab work, imaging, and care for newborns. It also covers assistant surgeons and the hospital doctors who manage your stay or your intensive care.
When you get care at an in-network hospital or surgery center, these providers can't ask you to give up your rights. If one of them is out-of-network, you generally owe only your in-network share. See out-of-network anesthesia at an in-network hospital for what to do with a bill like this.
Related terms
Guides that use this term
- GuideOut-of-network anesthesia at an in-network hospitalGot an out-of-network anesthesia bill after care at an in-network hospital? Federal law usually limits you to your in-network share. Here's what to do.
- GuideDoes the No Surprises Act apply to my bill?The No Surprises Act limits many surprise out-of-network bills. See when it applies, what it doesn't cover, and what to do if you get a surprise bill.
Sources
- Know your rights: health insurance and surprise billing, Centers for Medicare & Medicaid Services. Accessed September 30, 2026.
- 45 CFR 149.420: Preventing certain cases of balance billing for non-emergency services, Electronic Code of Federal Regulations. Accessed September 30, 2026.
This is general information, not legal or medical advice. Rules can depend on your plan and your state. Romi Care isn't an insurer, law firm, collection agency, or government program.