H70.20 ICD-10-CM Code: Unspecified petrositis
Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.
Coder workflow for H70.20
MedCoder structured workflow — derived from this code’s own official record
Before you code H70.20
- H70.20 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).
ReviewH70.201, H70.202, H70.203, H70.209
See the relationships section · Guide: How to choose an ICD-10-CM code →
- Unspecified does not mean incorrect. When the record gives no greater specificity, H70.20 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by acute versus chronic. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).
See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →
Choose the right path
- Does the documentation support one of the more specific codes beneath H70.20?
Yes → Select that code and continue the checks below on its own page.
No → H70.20 cannot be reported as written; query for the specificity its subcategory needs. - Does the record document the detail a more specific sibling code needs?
Yes → Review the specific siblings in this subcategory.
No → Continue — H70.20 is appropriate when the documentation goes no further.
Consider H70.20. 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).
- 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).
- Any detail beyond this code’s title
- What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.
Coding decision scenarios
Pattern scenarios for this code’s structure — decision rules, not clinical cases
Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.
Coding question: Is a more specific sibling code supportable?
Path: Review the specific siblings in this subcategory and what each requires the record to state.
Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).
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
MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.
Verify Before Coding
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 H70.20 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 2 Excludes2 notes across 2 chapters: H74 — Other disorders of middle ear mastoid (via H70.-), M86 — Osteomyelitis (via H70.2.-).
These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.
Contextual Map
Every relationship of H70.20 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 H70.20 with these 2 related codes in Claim Check
Hierarchy
- H60-H95 — Chapter 8: Diseases of the Ear and Mastoid Process (H60-H95) (H60-H95)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H65-H75 — Diseases of middle ear and mastoid[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
Referenced by Excludes2 notes
- H74 — Other disorders of middle ear mastoid[Excludes2](via H70.-): “mastoiditis (H70.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
- M86 — Osteomyelitis[Excludes2](via H70.2.-): “petrous bone (H70.2-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
Nearest codes (40)
- H70 — Mastoiditis and related conditions[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H70.001 — Acute mastoiditis without complications, right ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H70.002 — Acute mastoiditis without complications, left ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H70.003 — Acute mastoiditis without complications, bilateral[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H70.009 — Acute mastoiditis without complications, unspecified ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H70.01 — Subperiosteal abscess of mastoid[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H70.011 — Subperiosteal abscess of mastoid, right ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- H70.012 — Subperiosteal abscess of mastoid, left ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- and 32 more
Change history
- FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016
Common coding questions
Can H70.20 be billed directly?
No. H70.20 (Unspecified petrositis) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
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
- Claim edits Official source data
- CMS Definitions of Medicare Code Edits — v43.1 (April 2026) 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. "H70.20 — Unspecified petrositis." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/h70.20-unspecified-petrositis
Change history
- FY2016 — October 1, 2015In the code set at ICD-10-CM adoptionUnspecified petrositis
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 H70.20 in its code family, with their registry titles.
- H70.10 — Chronic mastoiditis, unspecified ear
- H70.11 — Chronic mastoiditis, right ear
- H70.12 — Chronic mastoiditis, left ear
- H70.13 — Chronic mastoiditis, bilateral
- H70.2 — Petrositis
- H70.201 — Unspecified petrositis, right ear
- H70.202 — Unspecified petrositis, left ear
- H70.203 — Unspecified petrositis, bilateral
- H70.209 — Unspecified petrositis, unspecified ear
- H70.21 — Acute petrositis