CO-183 denial code
The referring provider is not eligible to refer the service billed
How to fix it
Confirm the referring provider's NPI, enrolment and eligibility to refer, then correct and resubmit.
How to prevent it
Validate referring providers against the payer registry before submission.
In practice
An imaging centre bills a CT ordered by a physician who recently left a group practice. The claim returns CO-183: the referring provider is not eligible to refer the service billed.
The ordering physician is a real, licensed doctor. What has failed is that his Medicare enrolment record is tied to the old group and his individual PECOS record has lapsed, so the payer cannot validate him as an eligible ordering provider.
Correcting the claim is not possible, because nothing on the claim is wrong. Either the ordering physician updates his enrolment, or the service is re-ordered by a provider whose record validates. Both take time the filing window is spending.
What sits behind it
For Medicare, ordering and referring providers must have a current individual enrolment record, and the requirement applies to specialties that never submit a claim of their own. That produces a structural problem: the party whose record is broken has no financial incentive to fix it, and the party losing the money cannot fix it for them.
Diagnostic services, durable medical equipment, home health and laboratory bear most of this volume, because they bill for services somebody else ordered. A practice in one of those lines is exposed to the enrolment hygiene of every referral source it accepts.
The only real defence is validating ordering providers against the payer registry before submission rather than after denial. Where a referral source repeatedly fails validation, that is worth raising with them directly — it is usually an oversight they can correct in an afternoon, and it is denying their patients' claims as well as yours.
Related codes
Terms used here — NPI · Credentialing · Claim Scrubbing
How we handle it — Provider Credentialing · Claims Management · Denial Management
Primary sources
The rules behind CO-183, at the bodies that publish them.
- PECOS Medicare enrollment (opens in a new tab)
Centers for Medicare & Medicaid Services — Where Medicare provider enrollment is filed and maintained. Revalidation deadlines missed here stop payment outright.
- NPI Registry (NPPES) (opens in a new tab)
Centers for Medicare & Medicaid Services — Public lookup and management for National Provider Identifiers. A stale NPPES record is a quietly common cause of enrollment and claim rejections.
- Medicare Claims Processing Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — The operative manual for how Medicare claims must be coded, submitted, adjusted and appealed. When a payer policy and a vendor's advice disagree, this settles it.
Every denial code with a guide
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Liability and workers comp
Patient responsibility
Provider eligibility
- CO-185Rendering Provider Not Eligible
- CO-183Referring Provider Not Eligible
Timely filing
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-183
Because ordering and referring providers must hold their own current enrolment record, separately from whoever performs and bills the service. A lapsed or incorrectly linked record on the ordering physician invalidates the claim even when everything about the rendering provider is correct.
Usually not, because nothing on the claim is wrong. The fix is either the ordering provider updating their enrolment record, or the service being re-ordered by a provider whose record validates. Both take time, so the filing deadline should be watched.
Those that bill for services ordered by someone else — imaging, laboratory, durable medical equipment and home health. They are exposed to the enrolment status of every referral source they accept, which is outside their control.
Validate ordering and referring providers against the payer registry during claim scrubbing, before submission. Where a referral source fails repeatedly, contact them: it is usually an unnoticed lapse that is denying their own patients' claims too.
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