2026 ICD-10-CM Diagnosis Code A69.21Meningitis due to Lyme disease

ICD-10-CM Codes›A00–B99›A65-A69›A69

ICD-10-CM A69.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A69.21 is a billable ICD-10-CM diagnosis code for meningitis due to Lyme disease. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 867 through 869. Coders also document this condition as borrelia infection of central nervous system. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Meningitis; and Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
A69.21
Billable Status
Yes — Valid for Submission
Code Describes
Meningitis due to Lyme disease
Short Description
Meningitis due to Lyme disease
Same as the full description in the CMS dataset.
Parent Code
A69.2
Lyme disease

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA65-A69Other spirochetal diseases
CategoryA69Other spirochetal infections
This CodeA69.21Meningitis due to Lyme disease

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Borrelia infection of central nervous system
  • Lyme neuroborreliosis
  • Meningitis caused by Spirochaetes
  • Meningitis in Lyme disease

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Meningitis(basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
      • in (due to)
        • Lyme disease

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS001
Meningitis
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Lyme Neuroborreliosis

    nervous system infections caused by tick-borne spirochetes of the borrelia burgdorferi group. the disease may affect elements of the central or peripheral nervous system in isolation or in combination. common clinical manifestations include a lymphocytic meningitis, cranial neuropathy (most often a facial neuropathy), polyradiculopathy, and a mild loss of memory and other cognitive functions. less often more extensive inflammation involving the central nervous system (encephalomyelitis) may occur. in the peripheral nervous system, b. burgdorferi infection is associated with mononeuritis multiplex and polyradiculoneuritis. (from j neurol sci 1998 jan 8;153(2):182-91)

Patient EducationClinical

Lyme Disease

Lyme disease is a bacterial infection you get from the bite of an infected tick. At first, Lyme disease usually causes symptoms such as a rash, fever, headache, and fatigue. But if it is not treated early, the infection can spread to your joints, heart, and nervous system. Prompt treatment can help you recover quickly.

The full article covers:

  • What is Lyme disease?
  • What causes Lyme disease?
  • Who is more likely to get Lyme disease?
  • What are the symptoms of Lyme disease?
  • How is Lyme disease diagnosed?
  • What are the treatments for Lyme disease?
  • Can Lyme disease be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert A69.21 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
088.81 Lyme disease
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About A69.21Overview

Is A69.21 (Lyme disease) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report meningitis due to Lyme disease on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does A69.21 group to?

When meningitis due to Lyme disease is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 868, 869, with relative weights from 0.7297 to 2.0932 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A69.21?

Under the General Equivalence Mappings, meningitis due to Lyme disease converts to ICD-9-CM 088.81 (Lyme disease). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.