2026 ICD-10-CM Diagnosis Code Q16.5Congenital malformation of inner ear

ICD-10-CM Codes›Q00-Q99›Q10-Q18›Q16

ICD-10-CM Q16.5
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q16.5 is a billable ICD-10-CM diagnosis code for congenital malformation of inner 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. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Congenital malformations of eye, ear, face, neck.

Code Identity

ICD-10-CM Code
Q16.5
Billable Status
Yes — Valid for Submission
Code Describes
Congenital malformation of inner ear
Short Description
Congenital malformation of inner ear
Same as the full description in the CMS dataset.
Parent Code
Q16
Congenital malformations of ear causing impairment of hearing

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ10-Q18Congenital malformations of eye, ear, face and neck
CategoryQ16Congenital malformations of ear causing impairment of hearing
This CodeQ16.5Congenital malformation of inner ear

Present on Admission (POA)Billing

Q16.5 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Aplasia of the cochlea and vestibular labyrinth
  • Cerebrospinal fluid otorrhea
  • Cerebrospinal fluid otorrhea due to congenital deformity of labyrinth
  • Complete deafness
  • Congenital abnormal shape of inner ear
  • Congenital absence of membranous labyrinth
  • Congenital anomaly of cochlea
  • Congenital anomaly of inner ear
  • Congenital anomaly of membranous labyrinth
  • Congenital anomaly of organ of Corti
  • Congenital anomaly of semicircular canal
  • Congenital anomaly of vestibule of inner ear
  • Congenital aplasia of inner ear
  • Congenital cochleovestibular malformation
  • Congenital deafness
  • Congenital deafness with labyrinthine aplasia, microtia and microdontia
  • Congenital deformity of labyrinth
  • Congenital dysplasia of ear vestibule
  • Congenital hypoplasia of semicircular canal
  • Congenital hypoplasia of vestibular structure of inner ear
  • Congenital malformation of bilateral inner ears
  • Congenital malformation of left inner ear
  • Congenital malformation of right inner ear
  • Incomplete development of membranous labyrinth
  • Incomplete formation of bony cochlea
  • Microdontia
  • Microtia
  • Mondini defect
  • Structural anomaly of the cochlea and vestibular labyrinth

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Congenital anomaly of membranous labyrinth
  • Congenital anomaly of organ of Corti

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Absence(of) (organ or part) (complete or partial)
      • ear, congenital
        • inner
    • Absence(of) (organ or part) (complete or partial)
      • inner ear, congenital
    • Absence(of) (organ or part) (complete or partial)
      • labyrinth, membranous
    • Absence(of) (organ or part) (complete or partial)
      • organ
        • of Corti, congenital
    • Agenesis
      • labyrinth, membranous
    • Agenesis
      • organ
        • of Corti
    • Anomaly, anomalous(congenital) (unspecified type)
      • ear (external)
        • inner
    • Anomaly, anomalous(congenital) (unspecified type)
      • labyrinth, membranous
    • Anomaly, anomalous(congenital) (unspecified type)
      • organ
        • of Corti
    • Aplasia
      • labyrinth, membranous
    • Collapse
      • labyrinth, membranous (congenital)
    • Deformity
      • ear (acquired)
        • congenital (external)
          • internal
    • Deformity
      • organ of Corti (congenital)
    • Degeneration, degenerative
      • membranous labyrinth, congenital (causing impairment of hearing)
    • Degeneration, degenerative
      • saccule, congenital (causing impairment of hearing)
    • Dilatation
      • saccule, congenital
    • Distortion(s) (congenital)
      • ear (auricle) (external)
        • inner
    • Distortion(s) (congenital)
      • organ
        • of Corti
    • Enlargement, enlarged
      • vestibular aqueduct
    • Malformation(congenital)
      • cochlea
    • Malformation(congenital)
      • ear
        • inner
    • Malformation(congenital)
      • internal ear
    • Malformation(congenital)
      • Mondini's (congenital) (malformation, cochlea)
    • Mondini's malformation(cochlea)

Clinical ClassificationClinical

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

CCSR MAL005
Congenital malformations of eye, ear, face, neck
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Cerebrospinal Fluid Otorrhea

    discharge of cerebrospinal fluid through the external auditory meatus or through the eustachian tube into the nasopharynx. this is usually associated with craniocerebral trauma (e.g., skull fracture involving the temporal bone;), neurosurgical procedures; or other conditions, but may rarely occur spontaneously. (from am j otol 1995 nov;16(6):765-71)

  • Cerebrospinal Fluid Otorrhea

    discharge of cerebrospinal fluid through the ear structures.

Patient EducationClinical

Birth Defects

A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy. One out of every 33 babies in the United States is born with a birth defect.

The full article covers:

  • What are birth defects?
  • What causes birth defects?
  • Who is at risk of having a baby with birth defects?
  • How are birth defects diagnosed?
  • What are the treatments for birth defects?
  • Can birth defects be prevented?

Read the full article at MedlinePlus

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

Convert Q16.5 to ICD-9-CMHistory

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

ICD-9-CM
744.05 Anomalies of inner ear
Exact Match The mapping is direct, with no qualifiers.

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 Q16.5Overview

Is Q16.5 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital malformation of inner ear on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does Q16.5 group to?

When congenital malformation of inner 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.

Is Q16.5 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for congenital malformation of inner ear on inpatient claims.

What is the ICD-9 equivalent of Q16.5?

Under the General Equivalence Mappings, congenital malformation of inner ear converts to ICD-9-CM 744.05 (anomalies of inner ear). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.