ICD-10-CM 2027 diagnosis code

H70Mastoiditis and related conditions

Not billable — use a more specific code

H70 is a header code, so it can't be reported by itself. Choose one of the 5 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About H70

H70 is the ICD-10-CM diagnosis code for mastoiditis and related conditions. It belongs to block H65-H75 (diseases of middle ear and mastoid) and chapter 8 (diseases of the ear and mastoid process). It is a header code, so it can't be reported by itself; one of its 5 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: H70.0 (mastoiditis), H70.1 (mastoiditis), H70.2 (petrositis), H70.8 (conditions) and H70.9 (mastoiditis).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under H70

Notes that apply from higher levels

Instructions written at a parent level also apply to H70.

Broader instructions also apply from Chapter 8: Diseases of the ear and mastoid process.

Codes whose notes reference H70

H74Excludes2

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about H70

Is H70 billable?: No. H70 is a header code. Report one of its more specific subcodes instead.