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

Compare with another code for A41.4Check this code on a claim

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
5 Excludes1 · 13 Excludes2 · 6 code-first instructions
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 2

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too, and is marked with where it comes from.

Code firstfrom A41Sequence the underlying condition before this code

+2 more in Instructions

Excludes1Not reported with this code unless documented as unrelated
  • gas gangrene (A48.0)
  • bacteremia NOS (R78.81) (from A41)
  • neonatal (P36.-) (from A41)
  • puerperal sepsis (O85) (from A41)

+1 more in Instructions

Excludes2from A41Not included here; may be reported together
  • sepsis (due to) (in) actinomycotic (A42.7)
  • sepsis (due to) (in) anthrax (A22.7)
  • sepsis (due to) (in) candidal (B37.7)
  • sepsis (due to) (in) Erysipelothrix (A26.7)

+9 more in Instructions

Where it sits Source: CMS/NCHS

Under:Chapter 1: Certain Infectious and Parasitic DiseasesA30-A49 Other bacterial diseasesA41 Other sepsis

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 791 — PREMATURITY WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 870 — SEPTICEMIA OR SEVERE SEPSIS WITH MV >96 HOURS (MDC 18)
  • MS-DRG 871 — SEPTICEMIA OR SEVERE SEPSIS WITHOUT MV >96 HOURS WITH MCC (MDC 18)
  • MS-DRG 872 — SEPTICEMIA OR SEVERE SEPSIS WITHOUT MV >96 HOURS WITHOUT MCC (MDC 18)
  • MS-DRG 974 — HIV WITH MAJOR RELATED CONDITION WITH MCC (MDC 25)
  • MS-DRG 975 — HIV WITH MAJOR RELATED CONDITION WITH CC (MDC 25)
  • MS-DRG 976 — HIV WITH MAJOR RELATED CONDITION WITHOUT CC/MCC (MDC 25)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 2 — Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock

Other models: CMS-HCC V22 HCC 2

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for A41.4 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on A41.4 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from A41

Code First

Underlying conditions that must be sequenced before this code.

  • Code first, if applicable, postprocedural sepsis (T81.44-)
  • sepsis due to central venous catheter (T80.211-)
  • sepsis during labor (O75.3)
  • sepsis following abortion, ectopic or molar pregnancy (O03.37, O03.87, O04.87, O07.37, O08.82)
  • sepsis following immunization (T88.0-)
  • sepsis following infusion, transfusion or therapeutic injection (T80.22-, T80.29-)

Source: inherited from A41

Coder workflow for A41.4

MedCoder structured workflow — derived from this code’s own official record

Before you code A41.4

  1. A41.4’s title joins a condition with an associated condition or complication. Confirm each component is documented. Where the classification presumes the link through the “with” convention, only a provider statement that the conditions are unrelated defeats it. A combination code is assigned only when it fully identifies the documented conditions; a required second code for the stage, type or manifestation is still reported when the notes ask for it (Guidelines I.B.9, I.A.15).

    Guide: Combination codes →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with A41.4. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in A41.4’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewA48.0, R78.81, P36, O85, A40

  2. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then A41.4.
    No → Continue; do not add an underlying condition the record does not document.

    ReviewT81.44, T80.211, O75.3, O03.37, O03.87, O04.87

Consider A41.4. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The associated condition or complication
Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).
The underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

Official instructions as workflow

  • Excludes1 — check before selecting A41.4(5 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with A41.4: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareA48.0, R78.81, P36, O85, A40

    See the official tabular notes · Guidelines I.A.12.a

  • Excludes2 — not part of A41.4(13 notes)

    Coding workflow: The conditions named in this note are not included in A41.4. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareA42.7, A22.7, B37.7, A26.7, A28.2, A54.86

    See the official tabular notes · Guidelines I.A.12.b

  • Code First — sequencing check(6 notes)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before A41.4. Do not add an underlying condition the record does not document.

    ReviewT81.44, T80.211, O75.3, O03.37, O03.87, O04.87

    See the official tabular notes · Guidelines I.A.13

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse A41.4 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of A41.4 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • A48.0— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of gas gangrene moves the case to A48.0; the two are not reported together unless documented as unrelated.

    Full comparison: A41.4 vs A48.0 →

  • R78.81— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of bacteremia NOS moves the case to R78.81; the two are not reported together unless documented as unrelated.

    Full comparison: A41.4 vs R78.81 →

  • P36— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of neonatal moves the case to P36; the two are not reported together unless documented as unrelated.

    Full comparison: A41.4 vs P36 →

  • O85— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of puerperal sepsis moves the case to O85; the two are not reported together unless documented as unrelated.

    Full comparison: A41.4 vs O85 →

  • A40— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of streptococcal sepsis moves the case to A40; the two are not reported together unless documented as unrelated.

    Full comparison: A41.4 vs A40 →

  • A41.2— Specificity relationship (Review)

    Overlapping diagnoses in the same category.

    Overlapping codes in the same category — the documentation decides which is the more specific fit.

    What moves you there: A record that documents no more than “Sepsis due to unspecified staphylococcus” takes A41.2; specificity in the record moves it back here.

    Full comparison: A41.4 vs A41.2 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Sepsis due to anaerobes is a billable ICD-10-CM diagnosis code (A41.4).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 15: Pregnancy, Childbirth, and the Puerperium (O00-O9A)

k. Puerperal sepsis Code O85, Puerperal sepsis, should be assigned with a secondary code to identify the causal organism (e.g., for a bacterial infection, assign a code from category B95-B96, Bacterial infections in conditions classified elsewhere). A code from category A40, Streptococcal sepsis, or A41, Other sepsis, should not be used for puerperal sepsis. If applicable, use additional codes to identify severe sepsis (R65.2-) and any associated acute organ dysfunction.

Coding Notes

MedCoder editorial — not official ICD-10-CM text; reviewed against the cited source

What this code means

A41.4 reports sepsis identified as due to anaerobic organisms. It sits in the A41 “other sepsis” category, which is where a documented systemic infection lands once the causal organism is known but has no more specific sepsis code of its own; when the organism is not further specified, the guidelines send the encounter to A41.9 instead.

Coding guidance

  • One code carries the sepsis itself. For a diagnosis of sepsis the guidelines assign the code for the underlying systemic infection — here, the anaerobic organism — and a code from subcategory R65.2 is added only when severe sepsis or an associated acute organ dysfunction is documented.
  • Severe sepsis is not assumed. R65.2- requires documented severe sepsis or an acute organ dysfunction the record ties to the sepsis; an organ dysfunction the documentation attributes to something else does not trigger it.
  • Post-procedural sepsis is sequenced differently: the code’s own Code First note routes sepsis following a procedure (T81.44-), a central venous catheter (T80.211-), labor (O75.3), abortion or ectopic pregnancy, immunization (T88.0-), or infusion/transfusion (T80.22-, T80.29-) ahead of A41.4.
  • Puerperal sepsis is excluded outright. The Chapter 15 guideline states that a code from A40 or A41 should not be used for puerperal sepsis — O85 carries it, with a secondary code for the organism.
  • Other organisms have their own sepsis codes: the Excludes2 list names candidal, gonococcal, herpesviral, listerial, meningococcal, anthrax, plague, tularemia and more. Excludes2 is the permissive note — those are different sepsis types coded in their own right, and a documented polymicrobial picture can carry more than one of them.

Decision-rule scenarios

Documentation: The record documents sepsis due to an anaerobic organism, with no organ dysfunction noted anywhere.

Coding question: Is a severe sepsis code added?

Rule: No — R65.2- is assigned only when severe sepsis or an associated acute organ dysfunction is documented. The deciding element is an explicit severe-sepsis statement or a documented organ dysfunction the record links to the sepsis.

Documentation: Anaerobic sepsis is documented as following a surgical procedure, with the provider stating the relationship.

Coding question: What is sequenced first?

Rule: The post-procedural infection codes lead per the Code First note and the postprocedural-sepsis guideline — the site-of-infection code first where known, then sepsis following a procedure (T81.44), with the organism code such as A41.4 identifying the agent. The deciding element is the provider documenting the relationship between the infection and the procedure.

Documentation: A note uses the term “urosepsis” with no further characterization.

Coding question: Does that support a sepsis code?

Rule: No — the guidelines state urosepsis is a nonspecific term, is not synonymous with sepsis, and has no default code in the Alphabetic Index; the provider must be queried for clarification.

Scenarios state the decision rule, not a code assignment — code selection always follows the provider's documentation and the ICD-10-CM Official Guidelines.

Documentation checklist

  • That the organism is anaerobic, distinguishing this from A41.9 and the organism-specific sepsis codes.
  • Severe sepsis or any acute organ dysfunction, and whether the record ties that dysfunction to the sepsis (decides R65.2-).
  • Any procedural, device, obstetric, or transfusion relationship the provider states (decides the Code First sequencing).

Codes are assigned from provider documentation; a coder never infers a diagnosis.

Common mistakes

  • Adding R65.2- without documented severe sepsis or a sepsis-associated acute organ dysfunction.
  • Coding from the term “urosepsis” instead of querying — the guidelines give it no default code.
  • Using an A41 code for puerperal sepsis, which the Chapter 15 guideline routes to O85.
  • Missing the Code First sequencing when the sepsis follows a procedure, device, or infusion.

Clinical context (coding perspective)

Negative or inconclusive blood cultures do not rule sepsis out — the guidelines say so explicitly, while also directing that the provider be queried. That matters for coders reading a chart whose cultures came back clean but whose clinical picture and provider statement say sepsis.

Written and reviewed by MedCoder against the official ICD-10-CM files; educational, not medical or billing advice. The official tabular notes and guidelines above take precedence in every case.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. Sequencing: 6 Code First instructions — the underlying condition is sequenced before this code when present. See the Code First notes
  2. 5 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  3. 13 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • MCC as a secondary diagnosis (FY2027). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name A41.4 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 3 Code First instructions across 2 chapters: I5A — Non-ischemic myocardial injury (non-traumatic) (via A41.-), N08 — Glomerular disorders in diseases classified elsewhere (via A41.-), N16 — Renal tubulo-interstitial disorders in diseases classified elsewhere (via A41.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Referenced by 6 Use Additional Code instructions across 2 chapters: J95.02 — Infection of tracheostomy stoma (via A41.-), K94.02 — Colostomy infection (via A41.-), K94.12 — Enterostomy infection (via A41.-), K94.22 — Gastrostomy infection (via A41.-), K95.01 — Infection due to gastric band procedure (via A41.-), K95.81 — Infection due to other bariatric procedure (via A41.-).

These codes instruct coders to additionally report this code when it applies.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: MCC — Major Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 46 clinically related codes on its CMS exclusion list. Does not count toward severity when the stay groups to DRGs 974-976 (HIV with Major Related Condition).

Named in the grouper logic of 8 MS-DRGs: DRG 791 (MDC 15), DRG 793 (MDC 15), DRG 870 (MDC 18), DRG 871 (MDC 18), DRG 872 (MDC 18), DRG 974 (MDC 25), DRG 975 (MDC 25), DRG 976 (MDC 25).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):INF002 — Septicemia (default); INF003 — Bacterial infections.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as MCC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

A39.4 — Meningococcemia, unspecified, A40.0 — Sepsis due to streptococcus, group A, A40.1 — Sepsis due to streptococcus, group B, A40.8 — Other streptococcal sepsis, A40.9 — Streptococcal sepsis, unspecified, A41.01 — Sepsis due to Methicillin susceptible Staphylococcus aureus, A41.02 — Sepsis due to Methicillin resistant Staphylococcus aureus, A41.1 — Sepsis due to other specified staphylococcus, A41.2 — Sepsis due to unspecified staphylococcus, A41.3 — Sepsis due to Hemophilus influenzae, A41.50 — Gram-negative sepsis, unspecified, A41.51 — Sepsis due to Escherichia coli [E. coli], A41.52 — Sepsis due to Pseudomonas, A41.53 — Sepsis due to Serratia, A41.54 — Sepsis due to Acinetobacter baumannii, A41.59 — Other Gram-negative sepsis, A41.81 — Sepsis due to Enterococcus, A41.89 — Other specified sepsis, A41.9 — Sepsis, unspecified organism, A42.7 — Actinomycotic sepsis, +25 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock) for risk-adjusted payment.

A40.0 — Sepsis due to streptococcus, group A, A40.1 — Sepsis due to streptococcus, group B, A40.3 — Sepsis due to Streptococcus pneumoniae, A40.8 — Other streptococcal sepsis, A40.9 — Streptococcal sepsis, unspecified, A41.01 — Sepsis due to Methicillin susceptible Staphylococcus aureus, A41.02 — Sepsis due to Methicillin resistant Staphylococcus aureus, A41.1 — Sepsis due to other specified staphylococcus, A41.2 — Sepsis due to unspecified staphylococcus, A41.3 — Sepsis due to Hemophilus influenzae, A41.50 — Gram-negative sepsis, unspecified, A41.51 — Sepsis due to Escherichia coli [E. coli], A41.52 — Sepsis due to Pseudomonas, A41.53 — Sepsis due to Serratia, A41.54 — Sepsis due to Acinetobacter baumannii, A41.59 — Other Gram-negative sepsis, A41.81 — Sepsis due to Enterococcus, A41.89 — Other specified sepsis, A41.9 — Sepsis, unspecified organism, A42.7 — Actinomycotic sepsis, +31 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Septicemia, Bacterial infections).

A40.0 — Sepsis due to streptococcus, group A, A40.1 — Sepsis due to streptococcus, group B, A40.3 — Sepsis due to Streptococcus pneumoniae, A40.8 — Other streptococcal sepsis, A40.9 — Streptococcal sepsis, unspecified, A41.01 — Sepsis due to Methicillin susceptible Staphylococcus aureus, A41.02 — Sepsis due to Methicillin resistant Staphylococcus aureus, A41.1 — Sepsis due to other specified staphylococcus, A41.2 — Sepsis due to unspecified staphylococcus, A41.3 — Sepsis due to Hemophilus influenzae, A41.50 — Gram-negative sepsis, unspecified, A41.51 — Sepsis due to Escherichia coli [E. coli], A41.52 — Sepsis due to Pseudomonas, A41.53 — Sepsis due to Serratia, A41.54 — Sepsis due to Acinetobacter baumannii, A41.59 — Other Gram-negative sepsis, A41.81 — Sepsis due to Enterococcus, A41.89 — Other specified sepsis, A41.9 — Sepsis, unspecified organism, A42.7 — Actinomycotic sepsis, +392 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Sepsis”; these codes share that main term but sit in a different category of the Tabular List.

A32.7 — Listerial sepsis (Listeria monocytogenes), A39.1 — Waterhouse-Friderichsen syndrome (adrenal hemorrhage syndrome), A39.2 — Acute meningococcemia (meningococcal, acute), A39.3 — Chronic meningococcemia (meningococcal, chronic), A39.4 — Meningococcemia, unspecified (meningococcal), A40.0 — Sepsis due to streptococcus, group A (Streptococcus, streptococcal, group, A), A40.1 — Sepsis due to streptococcus, group B (Streptococcus, streptococcal, group, B), A40.3 — Sepsis due to Streptococcus pneumoniae (pneumococcal), A40.8 — Other streptococcal sepsis (Streptococcus, streptococcal, specified NEC), A40.9 — Streptococcal sepsis, unspecified (Streptococcus, streptococcal), A42.7 — Actinomycotic sepsis (actinomycotic), A54.86 — Gonococcal sepsis (gonococcal), B00.7 — Disseminated herpesviral disease (herpesviral), B37.7 — Candidal sepsis (candidal), J95.02 — Infection of tracheostomy stoma (tracheostomy stoma), K65.1 — Peritoneal abscess (intra-abdominal), O08.0 — Genital tract and pelvic infection following ectopic and molar pregnancy (following, abortion), O08.82 — Sepsis following ectopic and molar pregnancy (with, ectopic or molar pregnancy), O75.3 — Other infection during labor (during labor), O85 — Puerperal sepsis (puerperal, postpartum, childbirth), +44 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Blood Glucose Test, Gamma-glutamyl Transferase (GGT) Test

Contextual Map

Every relationship of A41.4 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run A41.4 with these 10 related codes in Claim Check

Hierarchy

Excludes1

  • A48.0 — Gas gangrene[Excludes1]: “gas gangrene (A48.0)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027

Referenced by Code First instructions

Referenced by Use Additional Code instructions

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 2 — Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

MDC crossing

  • MDC 15 — Newborns and Other Neonates with Conditions Originating in Perinatal Period[MDC crossing]: “Newborns and Other Neonates with Conditions Originating in Perinatal Period — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”— CMS MS-DRG Definitions Manual · FY2027
  • MDC 18 — Infectious and Parasitic Diseases, Systemic or Unspecified Sites[MDC crossing]: “Infectious and Parasitic Diseases, Systemic or Unspecified Sites — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 1 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Infection, infected, infective (opportunistic), Clostridioides, difficile, sepsis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Infection, infected, infective (opportunistic), Clostridium NEC, difficile, sepsis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Infection, infected, infective (opportunistic), Clostridium NEC, perfringens, sepsis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Infection, infected, infective (opportunistic), Clostridium NEC, welchii, sepsis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Sepsis (generalized) (unspecified organism), anaerobic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Sepsis (generalized) (unspecified organism), Gram-negative (organism), anaerobic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes (18)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Indexed Clinical Terms (6)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Common coding questions

MedCoder editorial

When is A41.4 used instead of A41.9?

When the record identifies the organism as anaerobic. The guidelines assign the code for the underlying systemic infection, and send the encounter to A41.9, Sepsis, unspecified organism, only when the type of infection or causal organism is not further specified. See Sepsis, severe sepsis and septic shock.

Does A41.4 need a severe sepsis code with it?

Only when severe sepsis or an associated acute organ dysfunction is documented — the guidelines state R65.2- should not be assigned otherwise, and an acute organ dysfunction the record attributes to something other than the sepsis does not qualify.

Does A41.4 risk-adjust?

Yes. A41.4 maps to HCC 2 under both CMS-HCC V28 and the older V22 model for payment year 2026 — the sepsis category, one of the higher-weighted acute categories in the model.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2027), quoted by section Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder-derived relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary, coding notes, decision checklist and FAQ answers MedCoder editorial explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "A41.4 — Sepsis due to anaerobes." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/a41.4-sepsis-due-to-anaerobes

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Sepsis due to anaerobes

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to A41.4 in its code family, with their registry titles.

View all codes in the A41 family