Skip to main content

H70.13 ICD-10-CM Code: Chronic mastoiditis, bilateral

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
1 Excludes1

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 152 — OTITIS MEDIA AND URI WITH MCC (MDC 03)
  • MS-DRG 153 — OTITIS MEDIA AND URI WITHOUT MCC (MDC 03)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for H70.13 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on H70.13 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Source: inherited from H70.1

Coder workflow for H70.13

MedCoder structured workflow — derived from this code’s own official record

Before you code H70.13

  1. Laterality is coded in this family. Confirm the side documented — right, left, or bilateral — and select the matching code (this page’s code: bilateral). The unspecified-side code applies only when the record states no side. Laterality is assigned from the documented side; where a bilateral code exists and both sides are documented, it is used instead of two unilateral codes (Guidelines I.B.13).

    See the relationships section · Guide: Laterality coding →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with H70.13. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in H70.13’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewA18.03

  2. Is the side documented?
    Yes → Select the code for the documented side (or the bilateral code when both sides are documented and one exists).
    No → Use the unspecified-side code only when the record states no side; a query is the alternative.

Consider H70.13. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
Laterality
Right, left or bilateral as documented; unspecified only when the record states no side (Guidelines I.B.13).
Acuity
Acute or chronic as documented; when both are documented and separate codes exist, both are reported with the acute code first (Guidelines I.B.8).

Official instructions as workflow

  • Excludes1 — check before selecting H70.13(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with H70.13: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareA18.03

    See the official tabular notes · Guidelines I.A.12.a

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition H70.13 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewA18.03

Documentation: The record documents the condition on one side only.

Coding question: Which code in this family applies?

Path: Select the sibling code for the documented side.

Reason: Laterality is assigned from the documented side; the unspecified-side code is for records that state no side (Guidelines I.B.13).

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Chronic mastoiditis, bilateral is a billable ICD-10-CM diagnosis code (H70.13).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Official Coding Guidelines

No excerpt in the ICD-10-CM Official Guidelines names this code specifically. Its chapter carries only this chapter-wide note:

Chapter 8: Diseases of the Ear and Mastoid Process (H60-H95)

Reserved for future guideline expansion

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name H70.13 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes2 note: H74 — Other disorders of middle ear mastoid (via H70.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 152 (MDC 03), DRG 153 (MDC 03).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):EAR002 — Diseases of middle ear and mastoid (except otitis media) (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Diseases of middle ear and mastoid (except otitis media)).

H70.012 — Subperiosteal abscess of mastoid, left ear, H70.013 — Subperiosteal abscess of mastoid, bilateral, H70.019 — Subperiosteal abscess of mastoid, unspecified ear, H70.091 — Acute mastoiditis with other complications, right ear, H70.092 — Acute mastoiditis with other complications, left ear, H70.093 — Acute mastoiditis with other complications, bilateral, H70.099 — Acute mastoiditis with other complications, unspecified ear, H70.10 — Chronic mastoiditis, unspecified ear, H70.11 — Chronic mastoiditis, right ear, H70.12 — Chronic mastoiditis, left ear, H70.201 — Unspecified petrositis, right ear, H70.202 — Unspecified petrositis, left ear, H70.203 — Unspecified petrositis, bilateral, H70.209 — Unspecified petrositis, unspecified ear, H70.211 — Acute petrositis, right ear, H70.212 — Acute petrositis, left ear, H70.213 — Acute petrositis, bilateral, H70.219 — Acute petrositis, unspecified ear, H70.221 — Chronic petrositis, right ear, H70.222 — Chronic petrositis, left ear, +204 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Mastoiditis”; these codes share that main term but sit in a different category of the Tabular List.

A18.03 — Tuberculosis of other bones (tuberculous), B89 — Unspecified parasitic disease (in, parasitic disease NEC), B99 — Other and unspecified infectious diseases (in, infectious disease NEC)

Contextual Map

Every relationship of H70.13 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run H70.13 with this related code in Claim Check

Hierarchy

Referenced by Excludes2 notes

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 03 — Diseases and Disorders of the Ear, Nose, Mouth and Throat[MDC crossing]: “Diseases and Disorders of the Ear, Nose, Mouth and Throat — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 5,147 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (40)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "H70.13 — Chronic mastoiditis, bilateral." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/h70.13-chronic-mastoiditis-bilateral

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Chronic mastoiditis, bilateral

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to H70.13 in its code family, with their registry titles.

View all codes in the H70 family