What does denial code CO-16 mean?

CO-16 means: The claim is missing required information or contains errors in how it was submitted. This is a general code that requires you to check the accompanying remark codes to understand the specific problem.. This RUC is received when a claim is submitted with missing, incorrect, or invalid information. For details pertaining to your claim, please refer to the remittance advice remark codes (RARCs) on the remittance advice (RA).

How do I resolve a CO-16 denial?

Correct the identified error and resubmit a corrected claim to avoid delay in payment and prevent a denial for untimely filing. See full Medicare contractor resolution steps at tryarceum.com.

Can I appeal a CO-16 denial?

CO-16 denials are generally not appealable. This represents a technical submission error that must be corrected and resubmitted rather than appealed.

CARC Code

16

🟡 Soft Denial

Missing Information or Billing Error

The claim is missing required information or contains errors in how it was submitted. This is a general code that requires you to check the accompanying remark codes to understand the specific problem.

missing info

Resolution: 87%Easy difficulty5-10 days avg

How to resolve this denial

Which payer denied this claim?

▶✓ Pre-action checklist — verify before contacting the payer

Check the RARC code — it tells you exactly which information is missing.
Was the referring/ordering provider NPI included when required?
Were all required modifiers present?
Is the diagnosis code specific enough (check for 'unspecified' ICD-10 codes)?

Still denied?

Formal Appeal

If the payer upheld the denial after reconsideration, you can submit a formal appeal.

Generate appeal letter →

▶More about CO-16 — stats, related codes, appeal template

87%

Recovery Rate

5-10 days

Avg. Resolution

Easy

Difficulty

Very Common

Frequency

Payer-Specific Notes

How major payers handle CARC 16 by specialty.

UnitedHealthcare

CARC 16 often paired with N4 — verify patient control number is populated in Loop 2300 REF

Aetna

Place of service code must be consistent with claim type (professional vs. institutional)

Common 835 Combinations

CARC 16 most often appears with these Group Code + RARC combinations on 835 remittances.

COCO-16+N257The claim was denied because the billing provider's primary identifier COCO-16+MA27The payer rejected this claim due to a missing, incomplete, or invalid COCO-16+N285The claim was denied due to a missing, incomplete, or invalid referring COCO-16+N382The payer denied the claim due to a missing, incomplete, or invalid patient COCO-16+N179The payer has identified missing information or billing errors on the claim and COCO-16+N23The claim contains a submission error or missing information that resulted in a COCO-16+N30The claim contains a submission error related to patient eligibility for the COCO-16+N286The claim was denied because the referring provider's primary identifier

Look up any combination →

Appeal Letter Template

Generic appeal template for CARC 16 denials.

We are resubmitting claim [CLAIM_NUMBER] for patient [PATIENT_NAME] (DOB: [DOB]) for date of service [DOS]. The original claim was denied under CARC 16 citing missing or incorrect information. We have corrected [SPECIFIC_FIELD] and are resubmitting as a corrected claim.

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