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A41.02

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codeA41.02
statusActive ✅

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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).
  • Do NOT add Z16.11 with A41.02 — Z16.11 carries an Excludes1 note against A41.02, since the resistant organism is already captured in the sepsis code itself. Z16.11 is only appropriate with other infection codes that don’t already specify MRSA.

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

(Note: these Excludes1/Excludes2 notes apply at the A41 category level, not solely to A41.02.)

  • Excludes1 — Bacteremia NOS — R78.81
  • Excludes1 — Neonatal sepsis — P36
  • Excludes1 — Puerperal sepsis — O85
  • Excludes1 — Streptococcal sepsis — A40.-
  • Excludes2 — Toxic shock syndrome — A48.3

(Removed: “Sepsis due to MSSA — A41.01” — this is not a formal Excludes note; A41.01 is simply the sibling code for the susceptible strain, selected instead of A41.02 based on documentation, not excluded from it.)

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 (Excludes1 with A41.02 — do not code together)

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.
  • Never assign Z16.11 alongside A41.02 — this is an Excludes1 edit pair and will trigger a coding error/audit flag.

Sources

ICD‑10‑CM A41.02 definition and DRG grouping — icd10data.com (2026 edition) AAPC Codify — A41 category Excludes1/Excludes2 notes AAPC Codify — Z16.11 Excludes1 note (A49.02, J15.212, A41.02)

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