G03.1 ICD-10-CM Code: Chronic meningitis

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G03.1 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 G03.1 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for G03.1

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

Before you code G03.1

1. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with G03.1. 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 G03.1’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.

   ReviewG04

Consider G03.1. 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).

Official instructions as workflow

• Excludes1 — check before selecting G03.1(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with G03.1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareG04

  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

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.

Indexed Clinical Terms (1)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Meningitis (basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic), chronic NEC

Don’t confuse G03.1 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of G03.1 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• G04— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of meningoencephalitis moves the case to G04; the two are not reported together unless documented as unrelated.

  Full comparison: G03.1 vs G04 →

• G03.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Meningitis, unspecified” takes G03.9; specificity in the record moves it back here.

  Full comparison: G03.1 vs G03.9 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 106 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 097 (MDC 01), DRG 098 (MDC 01), DRG 099 (MDC 01).

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

Clinical classification (AHRQ CCSR):NVS001 — Meningitis (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 process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

E13.638 — Other specified diabetes mellitus with other oral complications, E13.649 — Other specified diabetes mellitus with hypoglycemia without coma, E13.65 — Other specified diabetes mellitus with hyperglycemia, E13.69 — Other specified diabetes mellitus with other specified complication, E13.8 — Other specified diabetes mellitus with unspecified complications, G00.0 — Hemophilus meningitis, G00.1 — Pneumococcal meningitis, G00.2 — Streptococcal meningitis, G00.3 — Staphylococcal meningitis, G00.8 — Other bacterial meningitis, G00.9 — Bacterial meningitis, unspecified, G03.0 — Nonpyogenic meningitis, G03.2 — Benign recurrent meningitis [Mollaret], G03.8 — Meningitis due to other specified causes, G03.9 — Meningitis, unspecified, G04.2 — Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified, G61.0 — Guillain-Barre syndrome, G96.9 — Disorder of central nervous system, unspecified, G98.0 — Neurogenic arthritis, not elsewhere classified, G98.8 — Other disorders of nervous system, +85 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Meningitis).

B27.82 — Other infectious mononucleosis with meningitis, B27.92 — Infectious mononucleosis, unspecified with meningitis, B37.5 — Candidal meningitis, B38.4 — Coccidioidomycosis meningitis, B42.81 — Cerebral sporotrichosis, B45.1 — Cerebral cryptococcosis, B57.41 — Meningitis in Chagas' disease, D86.81 — Sarcoid meningitis, G00.0 — Hemophilus meningitis, G00.1 — Pneumococcal meningitis, G00.2 — Streptococcal meningitis, G00.3 — Staphylococcal meningitis, G00.8 — Other bacterial meningitis, G00.9 — Bacterial meningitis, unspecified, G01 — Meningitis in bacterial diseases classified elsewhere, G02 — Meningitis in other infectious and parasitic diseases classified elsewhere, G03.0 — Nonpyogenic meningitis, G03.2 — Benign recurrent meningitis [Mollaret], G03.8 — Meningitis due to other specified causes, G03.9 — Meningitis, unspecified, +27 more

Same Index main term, other category

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

B26.1 — Mumps meningitis (in, mumps), B27.92 — Infectious mononucleosis, unspecified with meningitis (in, infectious mononucleosis), B37.5 — Candidal meningitis (monilial), B38.4 — Coccidioidomycosis meningitis (in, coccidioidomycosis), B42.81 — Cerebral sporotrichosis (sporotrichosis), B45.1 — Cerebral cryptococcosis (cryptococcal), B49 — Unspecified mycosis (mycotic NEC), B56.9 — African trypanosomiasis, unspecified (in, African trypanosomiasis), B57.41 — Meningitis in Chagas' disease (in, Chagas' disease), B83.2 — Angiostrongyliasis due to Parastrongylus cantonensis (eosinophilic), B89 — Unspecified parasitic disease (in, parasitic disease NEC), G00.0 — Hemophilus meningitis (influenzal), G00.1 — Pneumococcal meningitis (bacterial, pneumococcal), G00.2 — Streptococcal meningitis (Streptococcal), G00.3 — Staphylococcal meningitis (staphylococcal), G00.8 — Other bacterial meningitis (Klebsiella), G00.9 — Bacterial meningitis, unspecified (septic), G93.2 — Benign intracranial hypertension (serous NEC), G96.198 — Other disorders of meninges, not elsewhere classified (ossificans), T79.8 — Other early complications of trauma (traumatic), +27 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

HIV Screening Test

Contextual Map

Every relationship of G03.1 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.

Hierarchy

• G00-G99 — Chapter 6: Diseases of the Nervous System (G00-G99) (G00-G99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G00-G09 — Inflammatory diseases of the central nervous system[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Clinical classification (CCSR)

• NVS001 — Meningitis[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 097 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH MCC[MS-DRG]: “NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 098 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH CC[MS-DRG]: “NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH CC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 099 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITHOUT CC/MCC[MS-DRG]: “NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITHOUT CC/MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — 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. 8,892 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Meningitis (basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic), chronic NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• G03 — Meningitis due to other and unspecified causes[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G03.0 — Nonpyogenic meningitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G03.2 — Benign recurrent meningitis [Mollaret][Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G03.8 — Meningitis due to other specified causes[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G03.9 — Meningitis, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

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

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G03.1 in its code family, with their registry titles.

• G03 — Meningitis due to other and unspecified causes
• G03.0 — Nonpyogenic meningitis
• G03.2 — Benign recurrent meningitis [Mollaret]
• G03.8 — Meningitis due to other specified causes
• G03.9 — Meningitis, unspecified

View all codes in the G03 family