2026 ICD-10-CM Diagnosis Code H91.21Sudden idiopathic hearing loss, right ear

ICD-10-CM Codes›H60–H95›H90-H94›H91

ICD-10-CM H91.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H91.21 is a billable ICD-10-CM diagnosis code for sudden idiopathic hearing loss, right ear. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 154 through 156. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hearing loss.

Code Identity

ICD-10-CM Code
H91.21
Billable Status
Yes — Valid for Submission
Code Describes
Sudden idiopathic hearing loss, right ear
Short Description
Sudden idiopathic hearing loss, right ear
Same as the full description in the CMS dataset.
Parent Code
H91.2
Sudden idiopathic hearing loss

Code Classification

ChapterH60–H95Diseases of the ear and mastoid process
SectionH90-H94Other disorders of ear
CategoryH91Other and unspecified hearing loss
This CodeH91.21Sudden idiopathic hearing loss, right ear

Clinical ClassificationClinical

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

CCSR EAR004
Hearing loss
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Hearing Disorders and Deafness

It's frustrating to be unable to hear well enough to enjoy talking with friends or family. Hearing disorders make it hard, but not impossible, to hear. They can often be helped. Deafness can keep you from hearing sound at all.

Read the full article at MedlinePlus

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

Convert H91.21 to ICD-9-CMHistory

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

ICD-9-CM
388.2 Sudden hearing loss 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 H91.21Overview

Is H91.21 (Sudden idiopathic hearing loss) a billable code?

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

What MS-DRG does H91.21 group to?

When sudden idiopathic hearing loss, right ear is the principal diagnosis on an inpatient stay, it groups to MS-DRG 154, 155, 156, with relative weights from 0.6911 to 1.5635 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of H91.21?

Under the General Equivalence Mappings, sudden idiopathic hearing loss, right ear converts to ICD-9-CM 388.2 (sudden hearing loss 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.