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A41.02

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🎗️ICD-10-CM A41.02 — Sepsis due to MRSA

Clinical Definition

ICD-10-CM A41.02 represents sepsis caused by Methicillin‑Resistant Staphylococcus aureus (MRSA). MRSA is a highly virulent, antibiotic‑resistant strain of S. aureus associated with severe systemic infection, rapid deterioration, and high mortality risk.

Clinical documentation should support:

  • Confirmed or strongly suspected MRSA as the causative organism
  • Evidence of sepsis (infection + organ dysfunction)
  • Clinical indicators such as elevated lactate, hypotension, altered mental status, leukocytosis/leukopenia, or organ failure
  • Source of infection when known (pneumonia, cellulitis, endocarditis, device‑related infection, etc.)

Coding Guidance

Key Coding Rules

  • Assign A41.02 when MRSA is documented as the cause of sepsis.
  • If documentation states “staph aureus sepsis” without MSSA/MRSA specification, default to A41.2.
  • If MSSA is documented, use A41.01 instead.
  • Add R65.20 or R65.21 when severe sepsis or septic shock is present.
  • Add codes for the underlying infection source (e.g., pneumonia, cellulitis, device infection).
  • Add Z16.11 if the provider documents antimicrobial resistance explicitly.

Sequencing

  • Principal diagnosis: A41.02 when sepsis is the reason for admission.
  • Secondary diagnosis: When sepsis develops after admission or is not the primary reason for encounter.

Includes / Excludes

Includes

  • MRSA septicemia
  • Sepsis due to MRSA
  • Severe sepsis or septic shock due to MRSA (with additional codes)

Excludes

  • MSSA sepsis — A41.01
  • Bacteremia NOS — R78.81
  • Neonatal sepsis — P36
  • Puerperal sepsis — O85
  • Streptococcal sepsis — A40.-
  • Toxic shock syndrome — A48.3

Code Tree

A41 Sepsis 
├── A41.0 Sepsis due to Staphylococcus aureus 
│ ├── A41.01 Sepsis due to MSSA 
│ └── A41.02 Sepsis due to MRSA 
├── A41.1 Sepsis due to other specified staphylococcus 
├── A41.2 Sepsis due to unspecified staphylococcus 
└── A41.9 Sepsis, unspecified organism

MS‑DRG Impact

MRSA sepsis is grouped into high‑acuity DRGs due to severity and resource utilization. ICD10Data.com

  • DRG 870 — Septicemia/Severe Sepsis with MV >96 hours
  • DRG 871 — Septicemia/Severe Sepsis without MV >96 hours with MCC
  • DRG 872 — Septicemia/Severe Sepsis without MV >96 hours without MCC

These DRGs significantly affect reimbursement and case mix index.

HCC Impact

  • HCC 2 — Sepsis, Severe Sepsis, and Septic Shock
  • High‑impact risk adjustment category
  • Requires clear documentation of sepsis criteria and MRSA as the causative organism

Documentation Requirements

To support A41.02, documentation should include:

  • MRSA identified or clinically suspected
  • Evidence of systemic infection and organ dysfunction
  • Source of infection (pneumonia, wound, device, urinary tract, etc.)
  • Clinical indicators: lactate, WBC abnormalities, hypotension, organ failure
  • Treatment: IV antibiotics, vasopressors, mechanical ventilation, ICU care

Coding Examples

Example 1

Documentation:
“Patient admitted with MRSA sepsis and acute respiratory failure.”

Codes:

Example 2

Documentation:
“MRSA pneumonia with sepsis. No shock.”

Codes:

Example 3

Documentation:
“Septic shock due to MRSA bacteremia.”

Codes:

  • A41.02 — Sepsis due to MRSA
  • R65.21 — Severe sepsis with septic shock
  • Add source of infection if known
  • A41.01 — Sepsis due to MSSA
  • A41.2 — Sepsis due to unspecified staphylococcus
  • R65.20 — Severe sepsis without shock
  • R65.21 — Severe sepsis with septic shock
  • J15.212 — MRSA pneumonia
  • Z16.11 — Resistance to penicillins (MRSA‑related resistance documentation)

Notes for Auditors & Coders

  • Confirm MRSA vs MSSA — this changes the code and DRG impact.
  • Ensure sepsis criteria are met; avoid coding based solely on positive cultures.
  • Query when documentation is unclear regarding organism, sepsis severity, or shock.
  • Validate sequencing rules based on reason for admission.

Sources

ICD‑10‑CM A41.02 definition and DRG grouping
Clinical criteria for MRSA sepsis
Excludes notes and coding guidance

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