H70.2 vs M86.8X59

H70.2 (Petrositis) compared with M86.8X59 (Other osteomyelitis, unspecified thigh), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because M86.8X59 lists H70.2 under Excludes2, which marks them as distinct conditions.

Official rule

What is different?

The conditions named, billing status and chapter.H70.2 is “Petrositis”; M86.8X59 is “Other osteomyelitis, unspecified thigh”. H70.2 is a non-billable header; M86.8X59 is billable. H70.2 sits in H60-H95 — Diseases of the Ear and Mastoid Process (H60-H95); M86.8X59 in M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99).

Registry fact

Can these codes be reported together?

Yes, when both are documented.M86.8X59 lists H70.2 under Excludes2: “petrous bone (H70.2-)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. M86.8X59 carries 5 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.M86.8X59’s tabular entry: “petrous bone (H70.2-)”. The note covers H70.2.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

One is a header.H70.2 is a non-billable header, but M86.8X59 is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

M86.8X59

Other osteomyelitis, unspecified thigh

↔

H70.2

Petrositis

What we found

Yes, when both are documented.M86.8X59 carries an Excludes2 note covering H70.2: “petrous bone (H70.2-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2 Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

Section I.A.12.b — Excludes2 · applies to: Excludes2
A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
ICD-10-CM Official Guidelines FY2026

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

	H70.2Petrositis	M86.8X59Other osteomyelitis, unspecified thigh
Billing status	Non-billable header Report instead: H70.201, H70.202, H70.203, H70.209, H70.211	Billable
Classification	H60-H95 — Diseases of the Ear and Mastoid Process (H60-H95)	M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)
Definition	Petrositis is a non-billable ICD-10-CM category code (H70.2).	Other osteomyelitis, unspecified thigh is a billable ICD-10-CM diagnosis code (M86.8X59).
Includes	Inflammation of petrous bone	—
Excludes1	—	osteomyelitis due to: echinococcus (B67.2) gonococcus (A54.43) salmonella (A02.24) postprocedural osteopathies (M96.-)
Excludes2	—	ostemyelitis of: orbit (H05.0-) petrous bone (H70.2-) vertebra (M46.2-)
Use additional code	—	code (B95-B97) to identify infectious agent code to identify major osseous defect, if applicable (M89.7-)

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

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Derived from the official CMS ICD-10-CM tabular data (FY2026). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources