ICD-10 Code H91.91: Unspecified hearing loss, right ear

Key Takeaways

H91.91 is the billable ICD-10-CM code for unspecified hearing loss of the right ear, valid for FY2026 (October 1, 2025 through September 30, 2026).

Laterality is encoded in the sixth character: right ear = 1, left ear = 2, bilateral = 3, unspecified ear = 0. Always use the most specific code available.

The parent code H91.9 is non-billable; H91.91 (right), H91.92 (left), or H91.93 (bilateral) must be used for claim submission.

Practice management software like Pabau helps audiology and ENT practices submit laterality-specific codes accurately, reducing denial rates.

ICD-10 Code H91.91 is a billable ICD-10-CM diagnosis code representing unspecified hearing loss of the right ear. Chapter 8 (Diseases of the ear and mastoid process, H60-H95) classifies it within the block covering Other disorders of ear (H90-H94), under category H91 (Other and unspecified hearing loss). The code is valid for the current fiscal year, from October 1, 2025 through September 30, 2026, per the CMS ICD-10-CM code files.

“Unspecified” in this context means the clinician has identified a right-ear hearing deficit, but hasn’t yet determined or documented the underlying cause, type (conductive, sensorineural, or mixed), or configuration. This guide covers billable status, the laterality coding framework, related codes, documentation requirements, and common coding pitfalls for practices billing under H91.91.

Code hierarchy and classification for H91.91

Understanding where H91.91 sits in the ICD-10-CM hierarchy prevents using a non-billable header code on a claim. The CDC/NCHS ICD-10-CM files organize codes from broad to specific, and only the most granular billable code should appear on a HIPAA-covered transaction.

ICD-10-CM requires the highest level of specificity available. Submitting H91.9 as a claim code instead of H91.91 causes rejection, because H91.9 is a header code, not a valid diagnosis code for billing. Most payers follow HIPAA-compliant clinical documentation rules that require specific, billable codes on every transaction.

Laterality coding rules: H91.91 vs H91.90 vs H91.92 vs H91.93

Laterality is the most common source of claim denial for hearing loss codes. The sixth character of H91.91 encodes the ear affected. Payers will reject the claim, or ask for more documentation, when the chart names a specific ear but the claim uses the unspecified-ear variant (H91.90).

• H91.91 (right ear): Use when the encounter note, audiogram, or clinical assessment documents a right-ear hearing deficit. This is ICD-10 Code H91.91 in its standard application.
• H91.92 (left ear): Use when the findings are limited to the left ear.
• H91.93 (bilateral): Use when the chart documents hearing loss in both ears and the cause or type remains unspecified. Don’t pair H91.91 with H91.92 to represent bilateral loss. H91.93 is the correct single code.
• H91.90 (unspecified ear): Use only when the patient can’t cooperate with evaluation, the record genuinely lacks laterality data, or the visit is an initial contact where laterality isn’t yet known. Overusing H91.90 when the chart names a specific ear draws payer scrutiny.

A practical rule: if the audiogram or clinical note names a specific ear, match the code to that ear. The ICD-10-CM Official Guidelines state that “unspecified” codes fit only when no further detail is available in the record, not as a shortcut when the detail already exists.

Practices that routinely default to H91.90 risk payer audits and medical necessity queries. Good digital intake forms that capture laterality at registration cut down on downstream coding guesswork.

ICD-10 Code H91.91 in the broader H91 category

Category H91 covers hearing loss that doesn’t fit the conductive or sensorineural subtypes classified under H90. Knowing the sibling codes within H91 helps coders tell when H91.91 fits and when a more specific code exists, such as H90.3 for bilateral sensorineural hearing loss or H90.6.

H91.91 sits at the “least specific but laterality-correct” end of the H91 spectrum. If subsequent workup reveals the loss is presbycusis (H91.1x) or ototoxic in origin (H91.0x), update the code at the next encounter. ICD-10 diagnostic coding is built to gain specificity as clinical evidence accumulates. Avoid leaving an initial unspecified code in place permanently.

H91.91 vs H90: When to use each code

Coders frequently confuse H90 and H91 because both cover hearing loss. The distinction matters for payer adjudication and clinical accuracy. Audiology practices should understand the type-based split between H90 and H91 to code these encounters correctly.

• H90 (Conductive and sensorineural hearing loss): Use when audiometry or clinical assessment has established the type of hearing loss. H90 includes conductive-only, sensorineural-only, and mixed types, each with laterality subcodes.
• H91.91 (Unspecified hearing loss, right ear): Use when the right ear is affected but clinicians haven’t yet determined the type. Common scenarios include a first-visit patient awaiting audiometry, or a patient who reports subjective hearing change without a confirmed audiometric profile.

If a patient’s audiogram clearly shows sensorineural loss in the right ear, H90.41 (sensorineural hearing loss, right) fits better than H91.91. Using ICD-10 Code H91.91 when H90 applies is a common coding mistake. It can affect medical necessity determinations, particularly for hearing aid authorizations and cochlear implant workups.

Documentation requirements for H91.91 claims

Claim denials for H91.91 most often trace back to thin documentation rather than the wrong code choice. The medical record must support every element of the code: the diagnosis of hearing loss, the unspecified nature, and the right-ear laterality.

What the chart must show for H91.91

• Laterality statement: The note must explicitly name the right ear. “Patient reports decreased hearing” without naming the ear doesn’t support H91.91 over H91.90.
• Reason for unspecified status: If the practice ordered audiometry but hasn’t completed it yet, document this in the note. Stating “audiogram pending, right-ear hearing deficit reported” satisfies payer rules for using an unspecified code while workup continues.
• Clinical basis for the encounter: Document the patient’s presenting complaint, relevant history (noise exposure, medications, prior ear conditions), and the exam findings that support the diagnosis.
• Referral context: If a clinician assigns H91.91 at a primary care visit pending audiology referral, document the referral plan. This strengthens the record if a payer reviews the claim.

The CDC/NCHS ICD-10-CM coding tool holds the official tabular list and index, which coders can check to confirm documentation rules for H91.91. Good medical forms at your practice capture the relevant detail at the point of service, cutting the need for documentation fixes after the fact.

Pabau’s patient record management system lets audiology and ENT teams build structured encounter templates. These templates prompt clinicians to document laterality, audiometric status, and referral plans on every hearing loss encounter, which cuts down on the missing documentation that drives H91.91 denials.

Reduce hearing loss claim denials with structured documentation

Pabau helps audiology and ENT practices capture laterality, audiometric findings, and referral plans at the point of care, supporting accurate ICD-10 coding from the first encounter.

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Coding guidelines and common pitfalls for H91.91

CMS and NCHS jointly maintain the ICD-10-CM Official Guidelines for Coding and Reporting, which govern when coders should use unspecified codes. Several guideline principles apply directly to H91.91.

Using unspecified codes appropriately for H91.91

ICD-10-CM guidelines permit unspecified codes when the medical record lacks specificity. They aren’t a shortcut for detail that exists but wasn’t recorded. If the chart documents “right sensorineural hearing loss confirmed by audiometry,” coding H91.91 instead of H90.41 is a coding error, even though H91.91 is technically billable.

Sequencing H91.91 as principal vs. secondary diagnosis

H91.91 may be the principal diagnosis when hearing loss is the main reason for the encounter. It can also appear as a secondary diagnosis when a clinician sees the patient for a related condition, such as tinnitus, ear pain, or vertigo, and right-ear hearing loss is a documented comorbidity.

Standard ICD-10-CM sequencing rules apply: code the condition chiefly responsible for the encounter first. In inpatient settings, the distinction between principal and secondary diagnosis affects claim adjudication and DRG assignment.

Updating H91.91 after workup

H91.91 fits at an initial or follow-up encounter when audiometric findings are pending. Once audiometry confirms the type of hearing loss, update the code at the next visit. Practices that leave H91.91 on the problem list after audiometry confirms a hearing loss type risk coding inaccuracies on future claims. Structured automated workflows can flag encounters where staff haven’t reviewed an unspecified hearing loss code after an audiogram result arrives.

Pairing H91.91 with CPT procedure codes

Coders frequently pair ICD-10 Code H91.91 with CPT codes for audiological evaluation. Common pairings include CPT 92551 or 92557 (audiometry screening and comprehensive audiometry), CPT 92553 (pure tone audiometry, air and bone), and CPT 92567 (tympanometry).

The ICD-10 diagnosis code must support the medical necessity of the procedure code. If a claim submits H91.91 with a CPT code for a procedure that requires a confirmed hearing loss type, payers may question medical necessity.

H91.91 synonyms, inclusions, and excludes notes

ICD-10-CM tabular notes apply at multiple levels of the H91 hierarchy and affect how coders can use H91.91. Review the notes at both the H91.9 subcategory level and the H91 category level, since these apply to all codes below them.

• Synonyms and inclusions at H91.91: The code captures right-ear hearing loss where clinicians haven’t determined the type (conductive, sensorineural, or mixed) and where the loss doesn’t arise from ototoxicity or age-related causes (presbycusis). It includes subjective right-ear hearing complaints that audiometric testing hasn’t yet characterized.
• Excludes1 at H91 category level: Abnormal auditory perception (H93.2-), hearing loss as classified in H90.- (conductive/sensorineural/mixed), impacted cerumen (H61.2-), noise-induced hearing loss (H83.3-), psychogenic deafness (F44.6), and transient ischemic deafness (H93.01-). Coders must code these conditions to their specific categories when the record documents them, not to H91.91. Impacted cerumen in particular is billed separately; see CPT 69210 for impacted cerumen removal for the related procedure code.
• No Excludes2 notes specific to H91.91: Unlike some ICD-10-CM codes, H91.91 carries no Excludes2 notes, so it doesn’t restrict which other conditions coders can report alongside it.

Getting H91.91 right on every claim

Most audiology and ENT claim denials for hearing loss codes come down to one preventable problem: the chart names a specific ear, but the claim uses the wrong code. ICD-10 Code H91.91 is the correct billable code when the record documents right-ear hearing loss and the type remains unspecified, but the code depends on structured encounter documentation to survive payer review.

Pabau’s claims management software and structured patient record templates help audiology and ENT practices capture laterality and audiometric status at every encounter. This supports accurate H91.91 coding from referral through resolution. To see how Pabau can help your practice document hearing loss claims correctly, book a demo with the team.

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