G03.9

Meningitis, unspecified

FY2027Chapter 6: Diseases of the nervous system/G00–G09 Inflammatory diseases of the central nervous system

BillableComplete code, valid to report

G03.9 (also written G039) is a billable ICD-10-CM diagnosis code for meningitis, unspecified. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 5 codes in category G03 (Meningitis due to other and unspecified causes). The Alphabetic Index lists it under 1 entry. Its coding notes include 2 Excludes1 entries and 8 Excludes2 entries.

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from G03 Meningitis due to other and unspecified causes
  • meningoencephalitis (G04.-)
  • meningomyelitis (G04.-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (8 notes)
Inherited from Chapter 6 Diseases of the nervous system
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

IRF 60% Rule

On the CMS list of diagnoses used to determine presumptive compliance with the IRF 60 percent rule.

Source: CMS IRF Presumptive Compliance-3, FY 2027 IRF PPS final rule files, effective for discharges on or after October 1, 2026

Hospital MCC

Counts as a major complication or comorbidity (MCC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 106 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

Includes

Further defines or gives examples of the content of the category.

Inherited from G03 Meningitis due to other and unspecified causes
  • arachnoiditis NOS
  • leptomeningitis NOS
  • meningitis NOS
  • pachymeningitis NOS

Inclusion terms

Conditions classified to this code.

This code
  • Arachnoiditis (spinal) NOS

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry