My plan says preventive care is free, so why did I get a bill for my checkup?

HealthCare.gov says most health plans must cover a set of preventive services, like screening tests, at no cost to you. This includes Marketplace plans [1]. In most cases you won't pay a copayment or coinsurance for services like immunizations and screening tests, even if you haven't met your deductible [1]. The page says these are generally covered at no cost when an in-network provider gives them. It also says coverage may vary, so "no cost" does not hold in every case [1].

The federal rule says a plan must not charge a copayment, coinsurance or deductible for items and services that have an A or B rating from the U.S. Preventive Services Task Force. It says the same for routine immunizations that the CDC advisory committee recommends [2].

The visit itself has its own rule [2]. If the service is billed separately from the office visit, the plan may charge cost sharing for the visit. If it is not billed separately and the main purpose of the visit is the service, the plan may not charge for the visit. If it is not billed separately and the main purpose is something else, the plan may charge for the visit [2]. In the rule's example, a cholesterol screening was billed apart from the office visit. The plan could not charge for the lab test, but it could charge for the visit [2]. Treatment that follows a screening is not part of the no-cost rule [2].

The rule does not require a plan with a network to cover these services out of network at no cost. But if the plan has no in-network provider who can give the service, it must cover the service out of network and may not charge cost sharing for it [2]. The sources here do not show how your claim was coded or whether your plan has a special rule. "Don't know yet" for your case.

Compare your EOB with the plan's list of preventive services and with the rule text in Source 2. The plan's own papers say how it applies this rule - "Don't know yet" for your plan.