2026 ICD-10-CM Diagnosis Code A49.01Methicillin susceptible Staphylococcus aureus infection, unspecified site

ICD-10-CM Codes›A00–B99›A30-A49›A49

ICD-10-CM A49.01
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A49.01 is a billable ICD-10-CM diagnosis code for methicillin susceptible Staphylococcus aureus infection, unspecified site. 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 infection caused by Panton-Valentine leukocidin producing Staphylococcus aureus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections.

Code Identity

ICD-10-CM Code
A49.01
Billable Status
Yes — Valid for Submission
Code Describes
Methicillin susceptible Staphylococcus aureus infection, unspecified site
Short Description
Methicillin suscep staph infection, unsp site
Parent Code
A49.0
Staphylococcal infection, unspecified site

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA30-A49Other bacterial diseases
CategoryA49Bacterial infection of unspecified site
This CodeA49.01Methicillin susceptible Staphylococcus aureus infection, unspecified site

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Infection caused by Panton-Valentine leukocidin producing Staphylococcus aureus
  • Staphylococcal infectious disease

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Methicillin susceptible Staphylococcus aureus (MSSA) infection
  • Staphylococcus aureus infection NOS

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.

    • Infection, infected, infective(opportunistic)
      • methicillin
        • susceptible Staphylococcus aureus (MSSA)
    • Infection, infected, infective(opportunistic)
      • staphylococcal, unspecified site
        • aureus (methicillin susceptible) (MSSA)
    • MSSA(Methicillin susceptible Staphylococcus aureus)
      • infection

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Staphylococcal Infections

Staphylococcus (staph) is a group of bacteria. There are more than 30 types. A type called Staphylococcus aureus causes most infections.

The full article covers:

  • What are Staphylococcal (staph) infections?
  • What causes staph infections?
  • Who is more likely to get a staph infection?
  • What are the symptoms of staph infections?
  • How are staph infections diagnosed?
  • What are the treatments for staph infections?
  • Can staph infections be prevented?

Read the full article at MedlinePlus

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

Convert A49.01 to ICD-9-CMHistory

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

ICD-9-CM
041.11 Mth sus Stph aur els/NOS
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 A49.01Overview

Is A49.01 (Staphylococcal infection, unspecified site) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report methicillin susceptible Staphylococcus aureus infection, unspecified site on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does A49.01 group to?

When methicillin susceptible Staphylococcus aureus infection, unspecified site 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 A49.01?

Under the General Equivalence Mappings, methicillin susceptible Staphylococcus aureus infection, unspecified site converts to ICD-9-CM 041.11 (mth sus Stph aur els/NOS). 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.