CO-234 Denial Code Description: What Healthcare Providers Need to Know in 2026
Note: This article covers CARC 234, a Claim Adjustment Reason Code used in medical billing. It does not cover the Nigeria +234 country code, Ohio’s 234 area code, or ICD-9 diagnosis code 234. If you are a healthcare provider or billing professional working a co 234 denial code on your remittance, you are in the […]
CO4 Denial Code: NCCI Modifier Conflicts, N519 Remark Code, and Specialty AR Workflows [2026]
![CO4 Denial Code: NCCI Modifier Conflicts, N519 Remark Code, and Specialty AR Workflows [2026]](https://oneosevenrcm.com/wp-content/uploads/2026/04/co-4-denial-code-ncci-modifier-hero-image-1_11zon-1024x536.webp)
IMPORTANT: Two Common Misconceptions About CO4 Misconception 1: Conifer Health describes CO4 as a service “excluded from the patient’s plan coverage.” This is factually wrong. Misconception 2: SPRY PT describes CO4 as a “duplicate claim.” This is also factually wrong. CO4 is not a coverage exclusion denial. It is not a duplicate claim denial. CO4 […]
CO-252 Denial Code: Complete Guide to Causes, RARC Codes, and Resolution
This guide covers the CO-252 denial code as defined by X12 and used in US healthcare claims processing under HIPAA. Australian Medicare uses a separate code numbered 252 to classify possible post-operative aftercare services — that code and this code share only a number, not a meaning. Every section of this guide is written specifically […]
CO-109 Denial Code: Description, Causes, and How to Fix It
According to X12, the official body that maintains Claim Adjustment Reason Codes, CARC 109 is defined as: “Claim/service not covered by this payer/contractor. You must send the claim/service to the correct payer/contractor.” In plain terms, the co 109 denial code means the claim you submitted landed at a payer that has no financial responsibility for […]
