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CO-158 Denial Code: Service Provided Outside the US

CO-158 means the payer is not paying because the service was provided outside the United States. Many plans, including Original Medicare in most situations, limit or exclude foreign care. It can also result from an incorrect service facility address.

Quick facts

Code
CO-158 (CARC 158)
Status
Active In use since September 30, 2003; last modified September 30, 2007.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The payer treats the amount as the provider's adjustment for this plan. It is often used when a network contract or program rule bars billing the patient.
  • PR (Patient Responsibility): The plan excludes foreign care and the patient is responsible, which is common when a traveling patient paid out of pocket and submitted the claim.
Official description
Service/procedure was provided outside of the United States.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-158 means

CARC 158 reads “Service/procedure was provided outside of the United States.” Some plans do not cover care received abroad, or cover it only for emergencies. When the payer determines the service location is outside the US, it adjusts the claim with this code.

For US-based providers, a true CO-158 is rare. It is more likely to show up on claims submitted by patients for care received while traveling, on claims from providers near the border, or on claims where an address field was entered incorrectly.

Example: a clinic updates its practice management system and the service facility country field defaults to a foreign value. Claims for that location begin coming back CO-158 even though the patients were seen in the US.

Common causes

  • Genuine foreign care under a plan that excludes or limits coverage outside the US.
  • Incorrect service facility address in box 32 or loop 2310C of the 837, including a country code.
  • Telehealth with the patient abroad, where the plan requires the patient to be in the US.
  • Military or overseas plans with different territory rules than the payer assumed.
  • Payer address data on file for the provider being out of date.

How to fix it

  1. Check where the service happened. Verify the patient location and the facility address on the claim.
  2. If an address was wrong, fix it in your system and submit a corrected claim with resubmission code 7.
  3. If care was truly abroad, read the plan’s foreign travel or emergency coverage terms. Some plans pay emergencies abroad and deny routine care.
  4. Appeal if the plan documents support coverage for the situation, such as an emergency, and include records showing the emergency.
  5. Direct the patient to any travel insurance or supplemental coverage they may have.

How to prevent it

  • Validate facility and billing addresses whenever locations are added or systems change.
  • Confirm patient location at the start of every telehealth visit and document it.
  • Tell traveling patients to check their plan’s foreign coverage before they leave.
  • Run pre-submission checks on address and country fields. The Claims Validator flags claim-data issues like these before the claim is sent.

Remark codes that may appear with CO-158

  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Directs you to plan documents describing coverage limits for care abroad.
  • CO-157 (Service/procedure was provided as a result of an act of war.): Another uncommon exclusion, for services resulting from an act of war.
  • PR-204 (This service/equipment/drug is not covered under the patient's current benefit plan): A general benefit-plan exclusion that is not specific to location.
  • CO-58 (Treatment was deemed by the payer to have been rendered in an inappropriate or invalid place of service.): The service was billed with an invalid place of service, which is about the setting rather than the country.

CO-158 FAQ

Does Medicare cover care outside the US?

Original Medicare generally does not, with limited exceptions such as certain emergencies near the Canadian or Mexican border. Medicare Advantage and Medigap plans may offer some foreign travel coverage, so check the specific plan.

Why did my US clinic get CO-158?

Check the service facility address in box 32 and the billing address in box 33. An incorrect country code, a foreign ZIP format, or a typo can make the payer think the service occurred abroad.

Can telehealth trigger CO-158?

It can if the patient was located outside the US during the visit and the plan limits coverage to services received in the United States. Payer rules on this vary, so check the policy.

Who submits claims for care received abroad?

Usually the patient. Foreign providers rarely bill US plans directly, so the member pays and submits an itemized bill, often with a translation and currency conversion, for any reimbursement the plan allows.