2026 ICD-10-CM Diagnosis Code H66.91Otitis media, unspecified, right ear

ICD-10-CM Codes›H60–H95›H65-H75›H66

ICD-10-CM H66.91
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H66.91 is a billable ICD-10-CM diagnosis code for otitis media, unspecified, right ear. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 152 through 153. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Otitis media.

This medical diagnosis code is frequently used in Pediatrics medical specialties to designate conditions such otitis media, unspecified.

Code Identity

ICD-10-CM Code
H66.91
Billable Status
Yes — Valid for Submission
Code Describes
Otitis media, unspecified, right ear
Short Description
Otitis media, unspecified, right ear
Same as the full description in the CMS dataset.
Parent Code
H66.9
Otitis media, unspecified

Code Classification

ChapterH60–H95Diseases of the ear and mastoid process
SectionH65-H75Diseases of middle ear and mastoid
CategoryH66Suppurative and unspecified otitis media
This CodeH66.91Otitis media, unspecified, right ear

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute otitis media of right ear with effusion
  • Acute otitis media with effusion
  • Acute right otitis media
  • Chronic otitis media after insertion of tympanic ventilation tube
  • Chronic otitis media of right ear
  • Chronic otitis media of right ear following insertion of tympanic ventilation tube
  • Infection of right ear
  • Middle ear effusion
  • Otitis media of right ear
  • Perforation of right tympanic membrane due to otitis media
  • Recurrent acute otitis media of right ear

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR EAR001
Otitis media
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Otitis Media

    inflammation of the middle ear including the auditory ossicles and the eustachian tube.

  • Otitis Media with Effusion

    inflammation of the middle ear with a clear pale yellow-colored transudate.

  • Otitis Media, Suppurative

    inflammation of the middle ear with purulent discharge.

Patient EducationClinical

Ear Infections

Ear infections are the most common reason parents bring their child to a doctor. Three out of four children will have at least one ear infection by their third birthday. Adults can also get ear infections, but they are less common.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert H66.91 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
382.9 Otitis media NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About H66.91Overview

Is H66.91 (Otitis media, unspecified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report otitis media, unspecified, right ear on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does H66.91 group to?

When otitis media, unspecified, right ear is the principal diagnosis on an inpatient stay, it groups to MS-DRG 152, 153, with relative weights from 0.7382 to 1.1822 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of H66.91?

Under the General Equivalence Mappings, otitis media, unspecified, right ear converts to ICD-9-CM 382.9 (otitis media NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.