A40.9 ICD-10-CM Code: Streptococcal sepsis, unspecified
A40.9 maps to CMS-HCC V28 2. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Other bacterial diseases (A30-A49)
A40.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceStreptococcal sepsis, unspecified
A serious bloodstream infection caused by streptococcal bacteria where the specific type of streptococcus has not been identified or documented. This is a life-threatening condition where bacteria have entered the blood and are multiplying throughout the body.
Buddy Insight
Streptococcal sepsis, unspecified, is used when documentation confirms streptococcal bloodstream infection but does not specify the streptococcal group or species.
CMS-HCC V28
MappedHCC 2
Coefficient HCC 2: 0.500 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 002
Code-level coefficient reference
ESRD/PACE
MappedHCC 2
Code-level coefficient reference
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for A40.9. Check the code and parent instructions in the Code Book.
Excludes 2
Official- carrier or suspected carrier of infectious disease (Z22.-)Inherited from A00-B99
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)Inherited from A00-B99
- infectious and parasitic diseases specific to the perinatal period (P35-P39)Inherited from A00-B99
- influenza and other acute respiratory infections (J00-J22)Inherited from A00-B99
Related Codes
Includes
Official- diseases generally recognized as communicable or transmissibleInherited from A00-B99
Excludes 1
Official- certain localized infections - see body system-related chaptersInherited from A00-B99, A40
- neonatal (P36.0-P36.1)Inherited from A00-B99, A40
- puerperal sepsis (O85)Inherited from A00-B99, A40
- sepsis due to Streptococcus, group D (A41.81)Inherited from A00-B99, A40
Code First
Official- , if applicable, postprocedural sepsis (T81.44-)Inherited from A40
- sepsis due to central venous catheter (T80.211-)Inherited from A40
- streptococcal sepsis during labor (O75.3)Inherited from A40
- streptococcal sepsis following abortion or ectopic or molar pregnancy (O03.37, O03.87, O04.87, O07.37, O08.82)Inherited from A40
- streptococcal sepsis following immunization (T88.0-)Inherited from A40
- streptococcal sepsis following infusion, transfusion or therapeutic injection (T80.22-, T80.29-)Inherited from A40
Use Additional
Official- code to identify resistance to antimicrobial drugs (Z16.-)Inherited from A00-B99
Code Also
OfficialNo Code Also instructions are included in this display for A40.9. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is A40.9 an HCC code?
Yes. A40.9 (Streptococcal sepsis, unspecified) maps to HCC 2, Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.500. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: A40.9 is billable and maps to V28 HCC 2, Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- A40.9
- Description
- Streptococcal sepsis, unspecified
- HCC (V28)
- HCC 2 — Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock
- RAF reference coefficient
- 0.500
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work A40.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for A40.9
For A40.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
A40.9 is the ICD-10-CM diagnosis code for streptococcal sepsis, unspecified. A serious bloodstream infection caused by streptococcal bacteria where the specific type of streptococcus has not been identified or documented. This is a life-threatening condition where bacteria have entered the blood and are multiplying throughout the body. A40.9 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other bacterial diseases (a30-a49).
Under the CMS-HCC V28 risk adjustment model, A40.9 maps to Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock (HCC 2) with a source-labeled community, non-dual, aged reference coefficient of 0.500. No V24 mapping is shown for A40.9; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Use this code only when the streptococcal organism is not further specified; if the specific streptococcal type (Group A, Group B, pneumococcal, etc.) is documented, use the more specific A40.0-A40.8 codes instead. For A40.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for A40.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the streptococcal organism is not further specified; if the specific streptococcal type (Group A, Group B, pneumococcal, etc.) is documented, use the more specific A40.0-A40.8 codes instead
- •Sepsis codes require documentation of systemic inflammatory response; ensure the clinical record clearly indicates sepsis diagnosis and consider querying the provider if only bacteremia or infection is documented without sepsis criteria
Clinical Significance
Streptococcal sepsis, unspecified, is used when documentation confirms streptococcal bloodstream infection but does not specify the streptococcal group or species. While it maps to the same HCC as specified codes, it represents suboptimal documentation specificity and may trigger coding quality audits.
Documentation Requirements
- ✓Blood cultures positive for Streptococcus species (group/species not further specified)
- ✓Clinical documentation of sepsis criteria met
- ✓Attempt to query the provider for specific streptococcal group or species identification
- ✓Severity and organ dysfunction assessment
- ✓Source of infection if identifiable
Commonly Confused Codes
- •A40.0/A40.1/A40.3/A40.8: Preferred specific codes when the streptococcal group is known; A40.9 is the fallback
- •A41.9 (Sepsis, unspecified organism): A40.9 specifies the organism is Streptococcus even if group is unknown; A41.9 is when the organism is completely unidentified
- •B95.5 (Unspecified streptococcus as the cause of diseases classified elsewhere): B95.5 is an additional code for the organism, not a sepsis code