CO-47 denial code
These diagnoses are not covered, missing or invalid
How to fix it
Confirm the diagnosis is valid for that date of service and supports the procedure under payer policy, then resubmit.
How to prevent it
Code set changes take effect by date of service; claims for December services submitted in January need the prior year's codes.
In practice
A practice bills a diagnostic study using an ICD-10-CM code that was retired in the October update, for a service delivered in September. The claim returns CO-47.
The code was entirely valid on the date of service. What failed is that the claim was built after the update using a table that no longer contains it, which is a system behaviour rather than a coding judgement.
Rebilling with the code valid for that date resolves it. Where instead the diagnosis is current but simply not covered for the procedure billed, the question is different: whether an accurate diagnosis exists that does support coverage, and if none does, the service is not payable.
What sits behind it
The code bundles three genuinely distinct problems and the remittance does not distinguish them. The diagnosis may be absent, invalid for the service date, or valid but excluded under the payer's policy. Establishing which one applies is the first step and determines everything after it.
Specificity accounts for a large share of the third category. ICD-10-CM requires coding to the highest level of detail documented, and an unspecified code where a specific one exists is frequently treated as not supporting coverage even though it is technically valid.
Laterality is the other recurring gap. Codes distinguishing right, left and bilateral are common in musculoskeletal and ophthalmic conditions, and payers increasingly reject unspecified laterality outright when the documentation clearly supports a side.
Related codes
Terms used here — ICD-10-CM · Medical Necessity · Claim Scrubbing
How we handle it — Medical Coding · Denial Management · Claims Management
Primary sources
The rules behind CO-47, at the bodies that publish them.
- CPT code set (opens in a new tab)
American Medical Association — Maintainer of CPT. Annual changes to CPT are the most common cause of a sudden, unexplained rise in denials each January.
- Claim Adjustment Reason Codes (CARC) (opens in a new tab)
X12 — The authoritative, maintained CARC list. Our denial code lookup explains these in plain English; X12 is where the canonical definitions live.
- National Correct Coding Initiative (NCCI) edits (opens in a new tab)
Centers for Medicare & Medicaid Services — The procedure-to-procedure and medically-unlikely edits behind most bundling denials. Checking these before submission prevents the denial entirely.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-47
Check in order. First confirm a diagnosis was submitted and pointed to the correct line. Then validate it against the code set in effect on the date of service. If both pass, the diagnosis is valid but not covered for that procedure, which is a policy question rather than a data one.
Frequently. Many payer policies list the specific codes that support coverage and exclude unspecified variants, so a code that is technically valid still fails the coverage test. Where the record documents laterality, severity or acuity, coding to that detail avoids the denial.
Only one the documentation supports. Adding a diagnosis the record does not establish is misrepresentation regardless of how plausible it is clinically. If the encounter genuinely involved a condition that was not coded, the note should show it before the claim does.
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