B44.0 maps to CMS-HCC V28 6. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupB44.0

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Mycoses (B35-B49)

B44.0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Invasive pulmonary aspergillosis

A serious fungal infection of the lungs caused by Aspergillus fungus that invades lung tissue, typically occurring in immunocompromised patients.

Buddy Insight

Invasive pulmonary aspergillosis is a life-threatening opportunistic infection with mortality rates of 30-95% depending on immune status and treatment timing.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 6

Opportunistic Infections

Coefficient HCC 6: 0.381 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 006

HHS-HCC 006 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 6

Opportunistic Infections

Code-level coefficient reference

RXHCC

Mapped

HCC 5

Opportunistic Infections

Code-level coefficient reference

Code Book Path

Official

B44Aspergillosis B44.0Invasive pulmonary aspergillosis

Inclusion Terms

Official

No inclusion terms are included in this display for B44.0. 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, B35-B49
infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)Inherited from A00-B99, B35-B49
infectious and parasitic diseases specific to the perinatal period (P35-P39)Inherited from A00-B99, B35-B49
influenza and other acute respiratory infections (J00-J22)Inherited from A00-B99, B35-B49
hypersensitivity pneumonitis due to organic dust (J67.-)Inherited from A00-B99, B35-B49
mycosis fungoides (C84.0-)Inherited from A00-B99, B35-B49

Related Codes

Official

B44.1Other pulmonary aspergillosis B44.2Tonsillar aspergillosis B44.7Disseminated aspergillosis B44.8Other forms of aspergillosis B44.9Aspergillosis, unspecified

Includes

Official

diseases generally recognized as communicable or transmissibleInherited from A00-B99, B44
aspergillomaInherited from A00-B99, B44

Excludes 1

Official

certain localized infections - see body system-related chaptersInherited from A00-B99

Code First

Official

No Code First sequencing instructions are included in this display for B44.0. Check the code and parent instructions in the Code Book.

Use Additional

Official

code to identify resistance to antimicrobial drugs (Z16.-)Inherited from A00-B99

Code Also

Official

No Code Also instructions are included in this display for B44.0. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

CT imaging with halo sign or air-crescent sign characteristic of invasive aspergillosis

Positive galactomannan antigen (serum or bronchoalveolar lavage) or culture/histopathology

Documented immunocompromised state: neutropenia, transplant, high-dose steroids, chemotherapy

Severity indicators: degree and duration of neutropenia, ICU admission, mechanical ventilation

MEAT Support

HCC Buddy guidance

CT imaging with halo sign or air-crescent sign characteristic of invasive aspergillosis

Positive galactomannan antigen (serum or bronchoalveolar lavage) or culture/histopathology

Documented immunocompromised state: neutropenia, transplant, high-dose steroids, chemotherapy

Severity indicators: degree and duration of neutropenia, ICU admission, mechanical ventilation

Audit Caution

HCC Buddy guidance

Confusing invasive aspergillosis with aspergilloma — an aspergilloma is a fungus ball in a pre-existing cavity and is NOT invasive disease

Using unspecified B44.9 when documentation clearly states 'invasive' — this loses clinical specificity

Failing to code the underlying immunocompromised condition which is required for complete clinical documentation

Not differentiating from allergic bronchopulmonary aspergillosis (B44.81) which maps to a different, lower-weight HCC

Common Mistakes

HCC Buddy guidance

B44.1 (Other pulmonary aspergillosis) - non-invasive forms including aspergilloma (fungus ball); invasive form penetrates lung tissue

B44.81 (Allergic bronchopulmonary aspergillosis) - an allergic response, NOT invasive infection; completely different pathophysiology and HCC mapping

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 B44.0 an HCC code?

Yes. B44.0 (Invasive pulmonary aspergillosis) maps to HCC 6, Opportunistic Infections under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.381. 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: B44.0 is billable and maps to V28 HCC 6, Opportunistic Infections. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: B44.0
Description: Invasive pulmonary aspergillosis
HCC (V28): HCC 6 — Opportunistic Infections
RAF reference coefficient: 0.381
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 6, Opportunistic Infections

0.381

ESRDHCC 6, Opportunistic Infections

Not separately weighted

RxHCCHCC 5, Opportunistic Infections

Not separately weighted

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 B44.0 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for B44.0

For B44.0, 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

B44.0 is the ICD-10-CM diagnosis code for invasive pulmonary aspergillosis. A serious fungal infection of the lungs caused by Aspergillus fungus that invades lung tissue, typically occurring in immunocompromised patients. B44.0 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering mycoses (b35-b49).

Under the CMS-HCC V28 risk adjustment model, B44.0 maps to Opportunistic Infections (HCC 6) with a source-labeled community, non-dual, aged reference coefficient of 0.381. 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.

Document the extent of pulmonary involvement and whether this is acute or chronic invasive aspergillosis. For B44.0, 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 B44.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document the extent of pulmonary involvement and whether this is acute or chronic invasive aspergillosis
•Verify patient's immunocompromised status (HIV, transplant, chemotherapy, etc.) as this is critical for clinical context

Clinical Significance

Invasive pulmonary aspergillosis is a life-threatening opportunistic infection with mortality rates of 30-95% depending on immune status and treatment timing. It primarily affects severely immunocompromised patients including those on chemotherapy, post-transplant immunosuppression, or with prolonged neutropenia.

Documentation Requirements

✓CT imaging with halo sign or air-crescent sign characteristic of invasive aspergillosis
✓Positive galactomannan antigen (serum or bronchoalveolar lavage) or culture/histopathology
✓Documented immunocompromised state: neutropenia, transplant, high-dose steroids, chemotherapy
✓Severity indicators: degree and duration of neutropenia, ICU admission, mechanical ventilation
✓Antifungal treatment documented (voriconazole as first-line, or amphotericin B)

Commonly Confused Codes

•B44.1 (Other pulmonary aspergillosis) - non-invasive forms including aspergilloma (fungus ball); invasive form penetrates lung tissue
•B44.81 (Allergic bronchopulmonary aspergillosis) - an allergic response, NOT invasive infection; completely different pathophysiology and HCC mapping