# CARC 256 denial code on dental claims > What does denial code CARC 256 mean on a dental claim, and can it be appealed? URL: https://dentovio.com/dental-claim-denial-codes/carc-256 Last verified: 2026-08-30 Dentovio is an independent publisher — not a payer, the ADA, X12, CAQH CORE, or any government agency. Code meanings and remark-code meanings on this page are Dentovio's own wording, written from the official X12 Claim Adjustment Reason Code and Remittance Advice Remark Code lists and linked back to them; X12 holds the copyright in those lists and its descriptions are not reproduced here. CDT codes are referenced by number only; CDT is the American Dental Association's copyrighted code set and this page does not reproduce ADA descriptors. Appealability verdicts are Dentovio editorial classification, not a standard. Every fact traces to the code steward's registry, a federal rule or manual, a HIPAA operating rule, an association publication, or a named payer's own document — never to a billing blog. This page was drafted with AI assistance and verified against the primary sources linked here. It has not been reviewed by a credentialed dental billing specialist, attorney, or clinician. Educational billing reference only — not billing, legal, or clinical advice. Plan contracts control individual outcomes, and processing policies usually live in the payer's provider manual rather than in the signed agreement. ## Direct answer On a dental remittance, CARC 256 means: A managed-care contract governs this service and does not pay for it. X12 assigns it no group code, so the group code on the remittance is the payer's choice under its own contract and it, not the CARC, decides who is assigned the balance. No source read for this page pairs a specific remark code with it. Dentovio's appealability verdict — structural: verify the plan terms. The managed-care agreement controls. What is worth checking is whether the right agreement was applied — a patient assigned to a different plan or product than the one the claim priced against produces this code with the wrong contract behind it. Registry entry: X12 Claim Adjustment Reason Code 256 — in the code set since 2013-06-02; active, with no deactivation date. Read on the list published 2025-11-01. Group code: X12 places no group-code restriction on 256, despite how often it is published as a CO code. The payer chooses. A group code always travels with a CARC, and it — not the CARC — assigns financial responsibility, so read the one on your remittance rather than assuming. ## What it means in dental context Read this as a contract fact rather than a benefit-design one: the question is what the managed-care agreement covering this patient says, not what the plan's general benefit summary says. The code is not dental-specific and never says DHMO — the same code carries medical HMO arrangements. ## Appealability: Structural — verify the plan terms The appealability verdicts on these pages are Dentovio's editorial classification. No standards body or payer publishes an appealability taxonomy: X12 defines what a code means, not what to do about it. Each verdict is built from the code's own mechanics and the payer and federal documents cited on the page, and it is a starting point for triage rather than a prediction of any outcome. The denial reflects a plan term such as an exclusion or exhausted limit. Verify that the payer used the correct plan and facts before deciding how the contract assigns responsibility. The managed-care agreement controls. What is worth checking is whether the right agreement was applied — a patient assigned to a different plan or product than the one the claim priced against produces this code with the wrong contract behind it. ## What to do 1. Confirm which managed-care product the patient was enrolled in on the date of service 2. Read the contract's covered-services schedule, not the general benefit summary 3. Check what the agreement says about billing the patient before posting a balance ## Remark codes No source read for this page pairs a remark code with CARC 256. X12 defines no CARC-to-RARC pairings at all: payer crosswalks are specific to that payer's own internal reason codes, and the CAQH CORE combination list binds only payers operating inside its business scenarios. Read the remark code on your own remittance. ## Read with this code - [CARC 96 — Not a covered benefit](https://dentovio.com/dental-claim-denial-codes/carc-96/index.html.md) - [CARC 204 — Not in the patient's plan](https://dentovio.com/dental-claim-denial-codes/carc-204/index.html.md) ## Sources - X12 Claim Adjustment Reason Codes (external code list 139) (list updated 2025-11-01): - X12 Remittance Advice Remark Codes (external code list 411) (list updated 2026-07-01): - 45 CFR 162.1602 — HIPAA adoption of the 835 remittance standard that carries these codes: ## Related - [Dental billing and claims hub](https://dentovio.com/dental-billing/index.html.md) - [All dental denial codes](https://dentovio.com/dental-claim-denial-codes/index.html.md) - [Payer documentation requirements](https://dentovio.com/dental-claim-documentation/index.html.md) - [Dental insurance prompt-pay laws by state](https://dentovio.com/dental-prompt-pay-laws/index.html.md) - [Dental claim appeal letters](https://dentovio.com/dental-claim-appeal-letters/index.html.md)