2027 ICD-10-CM Diagnosis Code H74.91Unspecified disorder of right middle ear and mastoid
ICD-10-CM Codes›H60–H95›H65-H75›H74
- Billable — Valid for Submission
- Not Chronic
H74.91 is a billable ICD-10-CM diagnosis code for unspecified disorder of right middle ear and mastoid. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 154 through 156. Coders also document this condition as disorder of right mastoid. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Diseases of middle ear and mastoid (except otitis media).
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Disorder of right mastoid
- Disorder of right middle ear
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to H74.91: its own notes plus those printed at H74 and Chapter 8. A note printed at a category, block or chapter applies to every code under it.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the ear condition, if applicable, to identify the cause of the ear condition
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Ear Disorders
An ear disorder is any condition that changes or harms the shape or structure of your ear. This can include abnormal ear shapes you're born with, injuries that change your ear's shape, and a growth on or in the ear.
The full article covers:
- What is an ear disorder?
- What causes ear disorders?
- What are the symptoms of ear disorders?
- How are ear disorders diagnosed?
- How are ear disorders treated?
- Can ear disorders be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert H74.91 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About H74.91Overview
What is the ICD-10 code for unspecified disorder of right middle ear and mastoid?
The ICD-10-CM code for unspecified disorder of right middle ear and mastoid is H74.91 (sometimes written as H7491). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is H74.91 (Unspecified disorder of middle ear and mastoid) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified disorder of right middle ear and mastoid on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does H74.91 group to?
When unspecified disorder of right middle ear and mastoid is the principal diagnosis on an inpatient stay, it groups to MS-DRG 156, 155, 154, with relative weights from 0.6656 to 1.5916 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of H74.91?
Under the General Equivalence Mappings, unspecified disorder of right middle ear and mastoid converts to ICD-9-CM 385.9 (dis mid ear/mastoid NOS). The mapping is approximate, so confirm the match fits the documentation.
