2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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 2027 (October 1, 2026 through September 30, 2027) 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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to H91.21: its own notes plus those printed at H91 and Chapter 8. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From H91 Other and unspecified hearing loss applies to 21 codes
  • abnormal auditory perception (H93.2-)
  • hearing loss as classified in H90.-
  • impacted cerumen (H61.2-)
  • noise-induced hearing loss (H83.3-)
  • psychogenic deafness (F44.6)
  • transient ischemic deafness (H93.01-)

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.

From Chapter 8 (H60-H95) Diseases of the ear and mastoid process applies to 653 codes
  • 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.

From Chapter 8 (H60-H95) Diseases of the ear and mastoid process applies to 653 codes
  • 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.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name H91.21, its category, or a range that includes it.

Applicable To 1

These notes mention H91.21.

  • Z82.2 Family history of deafness and hearing loss
    Conditions classifiable to H90-H91 names H90-H91, which includes this code

Excludes1 1

These codes carry an Excludes1 note naming H91.21: they are not reported together with it, unless the two conditions are unrelated.

  • H90 Conductive and sensorineural hearing loss
    sudden (idiopathic) hearing loss (H91.2-) names H91.2-, which includes this code

Code Also 1

These codes say H91.21 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • F80.4 Speech and language development delay due to hearing loss
    type of hearing loss (H90.-, H91.-) names H91.-, which includes this code

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About H91.21Overview

What is the ICD-10 code for sudden idiopathic hearing loss, right ear?

The ICD-10-CM code for sudden idiopathic hearing loss, right ear is H91.21 (sometimes written as H9121). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

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 156, 155, 154, with relative weights from 0.6656 to 1.5916 depending on complications. Higher weights mean higher Medicare reimbursement.

Can H91.21 be reported with a code from H93.2?

Not as a rule. The Excludes1 note at H91, which applies to H91.21, lists "abnormal auditory perception (H93.2-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

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.