2026 ICD-10-CM Diagnosis Code A41.4Sepsis due to anaerobes

ICD-10-CM Codes›A00–B99›A30-A49›A41

ICD-10-CM A41.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A41.4 is a billable ICD-10-CM diagnosis code for sepsis due to anaerobes. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 870 through 872, 974 through 976. Coders also document this condition as infection caused by Clostridium perfringens. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Septicemia.

Code Identity

ICD-10-CM Code
A41.4
Billable Status
Yes — Valid for Submission
Code Describes
Sepsis due to anaerobes
Short Description
Sepsis due to anaerobes
Same as the full description in the CMS dataset.
Parent Code
A41
Other sepsis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA30-A49Other bacterial diseases
CategoryA41Other sepsis
This CodeA41.4Sepsis due to anaerobes

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Infection caused by Clostridium perfringens
  • Sepsis caused by anaerobic bacteria
  • Sepsis caused by Bacteroides
  • Sepsis caused by Clostridium
  • Sepsis caused by Peptostreptococcus
  • Septic shock co-occurrent with acute organ dysfunction caused by anaerobic bacteria

Tabular List NotesGuidance

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

Type 1 Excludes

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)
      • Clostridioides
        • difficile
          • sepsis
    • Infection, infected, infective(opportunistic)
      • Clostridium NEC
        • difficile
          • sepsis
    • Infection, infected, infective(opportunistic)
      • Clostridium NEC
        • perfringens
          • sepsis
    • Infection, infected, infective(opportunistic)
      • Clostridium NEC
        • welchii
          • sepsis
    • Sepsis(generalized) (unspecified organism)
      • anaerobic
    • Sepsis(generalized) (unspecified organism)
      • Gram-negative (organism)
        • anaerobic

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR INF002
Septicemia
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Burkholderia Infections

    infections with bacteria of the genus burkholderia.

  • Lemierre Syndrome

    a superinfection of the damaged oropharyngeal mucosa by fusobacterium necrophorum leading to the secondary septic thrombophlebitis of the internal jugular vein.

  • Neonatal Sepsis

    blood infection that occurs in an infant younger than 90 days old. early-onset sepsis is seen in the first week of life and most often appears within 24 hours of birth. late-onset occurs after 1 week and before 3 months of age.

  • Pregnancy Complications, Infectious

    the co-occurrence of pregnancy and an infection. the infection may precede or follow fertilization.

  • Puerperal Infection

    an infection occurring in puerperium, the period of 6-8 weeks after giving birth.

  • Sepsis

    systemic inflammatory response syndrome with a proven or suspected infectious etiology. when sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. when sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock.

  • Sepsis-Associated Encephalopathy

    acute neurological dysfunction during severe sepsis in the absence of direct brain infection characterized by systemic inflammation and blood brain barrier perturbation.

  • Systemic Inflammatory Response Syndrome

    a systemic inflammatory response to a variety of clinical insults, characterized by two or more of the following conditions: (1) fever >38 degrees c or hypothermia <36 degrees c; (2) tachycardia >90 beat/minute; (3) tachypnea >24 breaths/minute; (4) leukocytosis >12,000 cells/cubic mm or 10% immature forms. while usually related to infection, sirs can also be associated with noninfectious insults such as trauma; burns; or pancreatitis. if infection is involved, a patient with sirs is said to have sepsis.

  • Burkholderia

    a genus of gram-negative, aerobic, rod-shaped bacteria originally classified as members of the pseudomonadaceae.

Patient EducationClinical

Sepsis

Sepsis is your body's overactive and extreme response to an infection. Sepsis is a life-threatening medical emergency. Without quick treatment, it can lead to tissue damage, organ failure, and even death.

The full article covers:

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

Read the full article at MedlinePlus

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

Convert A41.4 to ICD-9-CMHistory

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

ICD-9-CM
038.3 Anaerobic septicemia
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
995.91 Sepsis
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

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 A41.4Overview

Is A41.4 (Other sepsis) a billable code?

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

What MS-DRG does A41.4 group to?

When sepsis due to anaerobes is the principal diagnosis on an inpatient stay, it groups to MS-DRG 870, 871, 872, 974, 975, 976, with relative weights from 0.8945 to 6.9118 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A41.4?

Under the General Equivalence Mappings, sepsis due to anaerobes converts to ICD-9-CM 038.3 (anaerobic septicemia) and 995.91 (sepsis). 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.