2026 ICD-10-CM Diagnosis Code K12.33Oral mucositis (ulcerative) due to radiation
ICD-10-CM Codes›K00–K95›K00-K14›K12
- Billable — Valid for Submission
- Not Chronic
K12.33 is a billable ICD-10-CM diagnosis code for oral mucositis (ulcerative) due to radiation. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 157 through 159. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury, Diseases of mouth; excluding dental, and Nontraumatic dental conditions.
Code Identity
Code Classification
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Use Additional Code
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Mouth Disorders
Your mouth is one of the most important parts of your body. It has many different functions. It allows you to:
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Convert K12.33 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About K12.33Overview
What is the ICD-10 code for oral mucositis (ulcerative) due to radiation?
The ICD-10-CM code for oral mucositis (ulcerative) due to radiation is K12.33 (sometimes written as K1233). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is K12.33 (Oral mucositis (ulcerative)) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report oral mucositis (ulcerative) due to radiation on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does K12.33 group to?
When oral mucositis (ulcerative) due to radiation is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 157, 158, 159, with relative weights from 0.7085 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of K12.33?
Under the General Equivalence Mappings, oral mucositis (ulcerative) due to radiation converts to ICD-9-CM 528.01 (mucosits d/t antineo rx). The mapping is approximate, so confirm the match fits the documentation.
