2026 ICD-10-CM Diagnosis Code A39.51Meningococcal endocarditis

ICD-10-CM Codes›A00–B99›A30-A49›A39

ICD-10-CM A39.51
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A39.51 is a billable ICD-10-CM diagnosis code for meningococcal endocarditis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 288 through 290. Coders also document this condition as meningococcal carditis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Endocarditis and endocardial disease.

Code Identity

ICD-10-CM Code
A39.51
Billable Status
Yes — Valid for Submission
Code Describes
Meningococcal endocarditis
Short Description
Meningococcal endocarditis
Same as the full description in the CMS dataset.
Parent Code
A39.5
Meningococcal heart disease

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA30-A49Other bacterial diseases
CategoryA39Meningococcal infection
This CodeA39.51Meningococcal endocarditis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Meningococcal carditis
  • Meningococcal endocarditis

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.

    • Disease, diseased
      • heart (organic)
        • meningococcal
          • endocarditis
    • Endocarditis(chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
      • meningococcal
    • Infection, infected, infective(opportunistic)
      • meningococcal
        • endocardium
    • Infection, infected, infective(opportunistic)
      • meningococcal
        • heart
          • endocardium

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR CIR004
Endocarditis and endocardial disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Endocarditis

Endocarditis is sometimes called infective endocarditis. It's a rare but life-threatening inflammation of the lining inside your heart's chambers and valves (the endocardium).

The full article covers:

  • What is endocarditis?
  • What causes endocarditis?
  • Who is more likely to develop endocarditis?
  • What are the symptoms of endocarditis?
  • What other problems can endocarditis cause?
  • How is endocarditis diagnosed?
  • What are the treatments for endocarditis?
  • Can endocarditis be prevented?

Read the full article at MedlinePlus

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

Convert A39.51 to ICD-9-CMHistory

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

ICD-9-CM
036.42 Meningococc endocarditis
Exact Match The mapping is direct, with no qualifiers.

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 A39.51Overview

Is A39.51 (Meningococcal heart disease) a billable code?

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

What MS-DRG does A39.51 group to?

When meningococcal endocarditis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 288, 289, 290, with relative weights from 0.9297 to 2.7062 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A39.51?

Under the General Equivalence Mappings, meningococcal endocarditis converts to ICD-9-CM 036.42 (meningococc endocarditis). The mapping is a direct match.

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.