ICD-10 K12.3
Non-Billable HeaderOral mucositis (ulcerative)
About ICD-10-CM K12.3
ICD-10-CM code K12.3 represents Oral mucositis (ulcerative). This is a non-billable header code in the Digestive System chapter (block K12). The 2026 edition of ICD-10-CM K12.3 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under K12.3. Per CMS ICD-10-CM Tabular 2026.
- Mucositis (oral) (oropharyneal)
Type 2 Excludes
Not included here, the excluded code is not part of K12.3, but a patient may have both conditions at the same time. Both codes may be coded together when applicable.
- gastrointestinal mucositis (ulcerative) (K92.81)
- mucositis (ulcerative) of vagina and vulva (N76.81)
- nasal mucositis (ulcerative) (J34.81)
Medicare LCD Coverage for K12.3
Local Coverage Determinations (LCDs) from CMS MACs that list K12.3 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing K12.3.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but K12.3 doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with K12.3
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To K12.3
Other codes in section K00-K14 (Diseases of oral cavity and salivary glands).
ICD-10 K12.3, Billing FAQ
Is ICD-10 code K12.3 billable? +
No, K12.3 is a non-billable header code. Use a more specific child code from block K12 when submitting claims.
What other names or terms map to K12.3? +
ICD-10 K12.3 includes: Mucositis (oral) (oropharyneal).
What codes are Type 2 Excludes for K12.3? +
Type 2 Excludes (may be coded together when both conditions exist): gastrointestinal mucositis (ulcerative) (K92.81); mucositis (ulcerative) of vagina and vulva (N76.81); nasal mucositis (ulcerative) (J34.81)
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
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