A41.9 ICD-10-CM Code: Sepsis, unspecified organism

Code

A41.9

Description

Sepsis, unspecified organism

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 A41.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for A41.9

What This Code Means

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for A41.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

• •Only use A41.9 when the organism is truly unknown or unspecified; if any organism is identified, use the more specific A41.x code (such as A41.0 for Staphylococcus aureus or A41.1 for Streptococcus pneumoniae)
• •Sepsis coding requires documentation of the systemic inflammatory response; ensure the clinical record supports sepsis diagnosis and consider querying the provider if only bacteremia or infection is documented without sepsis criteria

Clinical Significance

Sepsis, unspecified organism, is used when sepsis is clinically diagnosed and documented but the causative organism is unknown or not identified through cultures. While it captures the sepsis diagnosis for risk adjustment, it represents the lowest specificity level and should be updated when organism identification becomes available.

Documentation Requirements

• ✓Clinical documentation of sepsis with systemic inflammatory response criteria met
• ✓Blood cultures drawn (even if negative or pending)
• ✓Documentation of presumed source of infection
• ✓Organ dysfunction assessment (renal, hepatic, respiratory, coagulopathy, altered mental status)
• ✓Antibiotic therapy initiated (reflects clinical judgment of sepsis even without positive cultures)

Commonly Confused Codes

• •R65.20 (Severe sepsis without septic shock): R65.20 is an additional code for severity, NOT a replacement for A41.9; use both when severe sepsis is present
• •R65.21 (Severe sepsis with septic shock): Same as above: always pair with a sepsis code like A41.9
• •A40/A41.0-A41.89: Any organism-specific sepsis code is preferred over A41.9 when the organism is known

Child Codes