2027 ICD-10-CM Diagnosis Code A27.81Aseptic meningitis in leptospirosis

ICD-10-CM Codes›A00–B99›A20-A28›A27

ICD-10-CM A27.81
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A27.81 is a billable ICD-10-CM diagnosis code for aseptic meningitis in leptospirosis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 23 through 24, 97 through 99. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 58 closely related codes. Coders also document this condition as leptospiral meningitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Meningitis.

Code Identity

ICD-10-CM Code
A27.81
Billable Status
Yes — Valid for Submission
Code Describes
Aseptic meningitis in leptospirosis
Short Description
Aseptic meningitis in leptospirosis
Same as the full description in the CMS dataset.
Parent Code
A27.8
Other forms of leptospirosis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA20-A28Certain zoonotic bacterial diseases
CategoryA27Leptospirosis
This CodeA27.81Aseptic meningitis in leptospirosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Leptospiral meningitis
  • Meningitis caused by Spirochaetes

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A27.81: its own notes plus those printed at Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

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

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name A27.81, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming A27.81: they are not reported together with it, unless the two conditions are unrelated.

  • G01 Meningitis in bacterial diseases classified elsewhere
    leptospirosis (A27.81)

Excludes2 1

These codes carry an Excludes2 note naming A27.81: its condition is not part of those codes, and both may be reported when the patient has both.

  • Block A65-A69 Other spirochetal diseases
    leptospirosis (A27.-) names A27.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR NVS001
Meningitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Leptospirosis

    infections with bacteria of the genus leptospira.

Patient EducationClinical

Bacterial Infections

Bacteria are tiny organisms (living things) that have only one cell. Under a microscope, they look like balls, rods, or spirals. They can be found almost everywhere on Earth. There are lots of bacteria in and on your body. In fact, your body has about 10 times more bacteria cells than human cells.

The full article covers:

  • What are bacteria?
  • How do bacterial infections spread?
  • What are the treatments for bacterial infections?
  • Can bacterial infections be prevented?

Read the full article at MedlinePlus

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

Convert A27.81 to ICD-9-CMHistory

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

ICD-9-CM
100.81 Leptospiral meningitis
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About A27.81Overview

What is the ICD-10 code for aseptic meningitis in leptospirosis?

The ICD-10-CM code for aseptic meningitis in leptospirosis is A27.81 (sometimes written as A2781). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is A27.81 (Other forms of leptospirosis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report aseptic meningitis in leptospirosis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does A27.81 group to?

When aseptic meningitis in leptospirosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 24, 98, 99, 23, 97, with relative weights from 1.5249 to 5.7422 depending on complications. Higher weights mean higher Medicare reimbursement.

Is A27.81 a CC or MCC?

CMS lists A27.81 as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 58 closely related codes in its exclusion list.

What is the ICD-9 equivalent of A27.81?

Under the General Equivalence Mappings, aseptic meningitis in leptospirosis converts to ICD-9-CM 100.81 (leptospiral meningitis). The mapping is a direct match.