ICD-10-CM 2027 diagnosis code
G09Sequelae of inflammatory diseases of central nervous system
G09 is a valid, billable ICD-10-CM code for sequelae of inflammatory diseases of central nervous system. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Looking up by condition? See ICD-10 code for Encephalitis or encephalomyelitis sequelae.
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 G09
G09 is the ICD-10-CM diagnosis code for sequelae of inflammatory diseases of central nervous system. It belongs to block G00-G09 (inflammatory diseases of the central nervous system) and chapter 6 (diseases of the nervous system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Code first: condition resulting from (sequela) of inflammatory diseases of central nervous system.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 091 (Other Disorders of Nervous System with MCC, relative weight 1.7046), DRG 092 (Other Disorders of Nervous System with CC, relative weight 1.0239) and DRG 093 (Other Disorders of Nervous System without CC/MCC, relative weight 0.7783), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 326 (late effects of intracranial abscess or pyogenic infection).
Coding notes
- condition resulting from (sequela) of inflammatory diseases of central nervous system
Notes that apply from higher levels
Instructions written at a parent level also apply to G09.
Broader instructions also apply from Chapter 6: Diseases of the nervous system.
Alphabetic index entries
14 entriesTerms in the official ICD-10-CM index that lead to G09.
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › cerebellum, cerebellar › sequelae
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › cerebral (embolic) › sequelae
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › extradural › brain › sequelae
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › subdural › brain › sequelae
- Parencephalitis › sequelae
- Sequelae (of) › abscess, intracranial or intraspinal (conditions in G06)
- Sequelae (of) › encephalitis or encephalomyelitis (conditions in G04)
- Sequelae (of) › infection, pyogenic, intracranial or intraspinal
- Sequelae (of) › meningitis › bacterial (conditions in G00)
- Sequelae (of) › meningitis › other or unspecified cause (conditions in G03)
- Sequelae (of) › phlebitis or thrombophlebitis of intracranial or intraspinal venous sinuses and veins (conditions in G08)
- Suppuration, suppurative › brain › sequelae
- Thrombophlebitis › cerebral (sinus) (vein) › sequelae
- Thrombophlebitis › intracranial venous sinus (any) › sequelae
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 01 · Diseases and Disorders of the Nervous System
ICD-9-CM equivalent
Converter →- 326Late effects of intracranial abscess or pyogenic infectionapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
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 G09
Is G09 billable?
- Yes. G09 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can G09 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict G09 as a principal diagnosis.
Is G09 a CC or MCC?
- No. G09 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does G09 group to?
- G09 is used in the MS-DRG v44.0 logic for MS-DRG 091 (Other Disorders of Nervous System with MCC), MS-DRG 092 (Other Disorders of Nervous System with CC) and MS-DRG 093 (Other Disorders of Nervous System without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for G09?
- The CMS General Equivalence Mappings map G09 to ICD-9-CM 326.