What is Out-of-Network?
Also called: non-participating provider · OON billing
Out-of-network claims usually require more documentation, are paid more slowly, and are far more likely to be paid directly to the patient rather than the provider — which turns a payer receivable into a patient receivable.
Where the No Surprises Act applies, balance billing is prohibited and the dispute moves to independent dispute resolution between provider and payer, on a defined timeline.
Primary sources
Where "Out-of-Network" is defined by the bodies that set the rules, rather than by us.
- No Surprises Act guidance (opens in a new tab)
Centers for Medicare & Medicaid Services — Balance billing restrictions, good faith estimates and the independent dispute resolution process — all of which change what a practice may bill a patient.
- Claims denials and appeals research (opens in a new tab)
KFF — Independent analysis of in-network denial rates and how rarely denials are appealed on the marketplace side. Useful counterweight to vendor-published statistics.
Last reviewed August 20, 2026
Related terms
Allowed Amount
The allowed amount is the maximum a payer recognizes for a covered service under its contract with the provider. It sets the ceiling on total payment — payer portion plus patient responsibility — and the difference between billed charge and allowed amount becomes a contractual adjustment.
Patient Responsibility
Patient responsibility is the portion of an allowed amount the patient owes: copay, coinsurance, deductible and non-covered charges. It is identified on the remittance by PR group codes, and it has become materially harder to collect as high-deductible plans have grown.
Superbill
A superbill is an itemized record of the services a provider delivered during a visit, listing diagnosis and procedure codes, provider details and charges. It is not a claim: it is the source document a biller converts into a claim, or that a patient submits to seek out-of-network reimbursement.
Credentialing
Credentialing is the verification of a provider's qualifications by a payer, and enrollment is the resulting contract that permits billing under that plan. The process commonly takes 90 to 180 days, and claims for services delivered before the effective date are generally not payable.
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