2026 ICD-10-CM Diagnosis Code R65.21Severe sepsis with septic shock

ICD-10-CM Codes›R00–R99›R50-R69›R65

ICD-10-CM R65.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R65.21 is a billable ICD-10-CM diagnosis code for severe sepsis with septic shock. 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. The code is not accepted as a principal diagnosis by the Medicare Code Editor. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Septicemia and Shock.

Code Identity

ICD-10-CM Code
R65.21
Billable Status
Yes — Valid for Submission
Code Describes
Severe sepsis with septic shock
Short Description
Severe sepsis with septic shock
Same as the full description in the CMS dataset.
Parent Code
R65.2
Severe sepsis

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR50-R69General symptoms and signs
CategoryR65Symptoms and signs specifically associated with systemic inflammation and infection
This CodeR65.21Severe sepsis with septic shock

Code EditsBilling

Medicare Code Editor checks that affect claim validity for R65.21.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Endotoxemia
  • Endotoxic shock
  • Endotoxicosis
  • Failed attempted termination of pregnancy complicated by shock
  • Failed attempted termination of pregnancy with septic shock
  • Hyperdynamic septic shock
  • Hypodynamic septic shock
  • Induced termination of pregnancy complicated by infectious disease
  • Induced termination of pregnancy complicated by postoperative shock
  • Induced termination of pregnancy complicated by septic shock
  • Induced termination of pregnancy complicated by shock
  • Miscarriage complicated by shock
  • Miscarriage with septic shock
  • Postprocedural septic shock
  • Pyrogenic shock
  • Sepsis caused by Chromobacterium
  • Septic shock
  • Septic shock co-occurrent with acute organ dysfunction caused by anaerobic bacteria
  • Septic shock co-occurrent with acute organ dysfunction caused by Haemophilus influenzae
  • Septic shock co-occurrent with acute organ dysfunction caused by Meningococcus
  • Septic shock co-occurrent with acute organ dysfunction caused by methicillin resistant Staphylococcus aureus
  • Septic shock co-occurrent with acute organ dysfunction caused by methicillin susceptible Staphylococcus aureus
  • Septic shock co-occurrent with acute organ dysfunction caused by Pneumococcus
  • Septic shock co-occurrent with acute organ dysfunction caused by Pseudomonas
  • Septic shock co-occurrent with acute organ dysfunction caused by Serratia
  • Septic shock co-occurrent with acute organ dysfunction caused by Streptococcus
  • Septic shock co-occurrent with acute organ dysfunction due to Chromobacterium
  • Septic shock co-occurrent with acute organ dysfunction due to coagulase-negative Staphylococcus
  • Septic shock co-occurrent with acute organ dysfunction due to Enterococcus
  • Septic shock co-occurrent with acute organ dysfunction due to Gonococcus
  • Septic shock co-occurrent with acute organ dysfunction due to Gram-positive coccus
  • Septic shock co-occurrent with acute organ dysfunction due to Group A streptococcus
  • Septic shock co-occurrent with acute organ dysfunction due to Group B streptococcus
  • Septic shock co-occurrent with acute organ dysfunction due to Staphylococcus
  • Septic shock due to transfusion
  • Septic shock following ectopic pregnancy
  • Septic shock following molar pregnancy
  • Shock due to ectopic pregnancy
  • Shock following molar pregnancy

Tabular List NotesGuidance

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

Type 1 Excludes

  • postprocedural septic shock T81.12

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)
      • with
        • organ dysfunction (acute)
          • with septic shock
    • Sepsis(generalized) (unspecified organism)
      • with
        • organ dysfunction (acute) (multiple)
          • with septic shock
    • Sepsis(generalized) (unspecified organism)
      • severe
        • with septic shock
    • Severe sepsis
      • with septic shock
    • Shock
      • endotoxic
    • Shock
      • gram-negative
    • Shock
      • septic (due to severe sepsis)

Clinical ClassificationClinical

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

CCSR INF002
Septicemia
Default principal diagnosis: inpatient No · outpatient Yes
CCSR SYM003
Shock
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Endotoxemia

    a condition characterized by the presence of endotoxins in the blood. on lysis, the outer cell wall of gram-negative bacteria enters the systemic circulation and initiates a pathophysiologic cascade of pro-inflammatory mediators.

  • Endotoxins

    toxins closely associated with the living cytoplasm or cell wall of certain microorganisms, which do not readily diffuse into the culture medium, but are released upon lysis of the cells.

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 R65.21 to ICD-9-CMHistory

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

ICD-9-CM
785.52 Septic shock
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
995.92 Severe 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 R65.21Overview

Is R65.21 (Severe sepsis) a billable code?

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

What MS-DRG does R65.21 group to?

On inpatient claims, severe sepsis with septic shock maps to MS-DRG 870, 871, 872, with relative weights from 1.0233 to 6.9118 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R65.21 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because severe sepsis with septic shock describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

What is the ICD-9 equivalent of R65.21?

Under the General Equivalence Mappings, severe sepsis with septic shock converts to ICD-9-CM 785.52 (septic shock) and 995.92 (severe 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.