B44.0 ICD-10-CM Code: Invasive pulmonary aspergillosis

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for B44.0 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on B44.0 itself; “inherited from” names the category or block whose note applies here.

This page already reflects the FY2027 tabular notes taking effect October 1, 2026.

Coder workflow for B44.0

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

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).

Official instructions as workflow

• Excludes2 — not part of B44.0(2 notes)

  Coding workflow: The conditions named in this note are not included in B44.0. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareJ67, C84.0

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

• Code Also — related condition(6 notes)

  Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

  ReviewJ4B, J32

  See the official tabular notes · Guidelines I.A.17

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.

Indexed Clinical Terms (1)

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.

• Aspergillosis (with pneumonia), pulmonary NEC, invasive

Don’t confuse B44.0 with…

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

The codes most likely to be picked instead of B44.0 — 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.

• B44.9— 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 “Aspergillosis, unspecified” takes B44.9; specificity in the record moves it back here.

  Full comparison: B44.0 vs B44.9 →

• J67— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypersensitivity pneumonitis due to organic dust adds J67; it is not part of this code and both may be reported when both are documented.

  Full comparison: B44.0 vs J67 →

• C84.0— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of mycosis fungoides adds C84.0; it is not part of this code and both may be reported when both are documented.

  Full comparison: B44.0 vs C84.0 →

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.

Verify Before Coding

• MCC as a secondary diagnosis (FY2026). 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 structured relationships — computed from published CMS and AHRQ datasets

Other codes that name B44.0 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 1 Excludes1 note: J17 — Pneumonia in diseases classified elsewhere.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Excludes2 note: J82 — Pulmonary eosinophilia, not elsewhere classified (via B44.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 1 Code First instruction: M01 — Direct infections of joint in infectious and parasitic diseases classified elsewhere (via B44.-).

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 1 Code Also instruction: J4B — Pulmonary mycetoma (via B44.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 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 129 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 177 (MDC 04), DRG 178 (MDC 04), DRG 179 (MDC 04).

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

Clinical classification (AHRQ CCSR):RSP016 — Other specified and unspecified lower respiratory disease (default); INF004 — Fungal 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.

A37.11 — Whooping cough due to Bordetella parapertussis with pneumonia, A37.81 — Whooping cough due to other Bordetella species with pneumonia, A37.91 — Whooping cough, unspecified species with pneumonia, A42.0 — Pulmonary actinomycosis, A43.0 — Pulmonary nocardiosis, A48.1 — Legionnaires' disease, B25.0 — Cytomegaloviral pneumonitis, B39.0 — Acute pulmonary histoplasmosis capsulati, B39.1 — Chronic pulmonary histoplasmosis capsulati, B39.2 — Pulmonary histoplasmosis capsulati, unspecified, B58.3 — Pulmonary toxoplasmosis, B59 — Pneumocystosis, B67.1 — Echinococcus granulosus infection of lung, J09.X1 — Influenza due to identified novel influenza A virus with pneumonia, J09.X2 — Influenza due to identified novel influenza A virus with other respiratory manifestations, J10.00 — Influenza due to other identified influenza virus with unspecified type of pneumonia, J10.01 — Influenza due to other identified influenza virus with the same other identified influenza virus pneumonia, J10.08 — Influenza due to other identified influenza virus with other specified pneumonia, J10.1 — Influenza due to other identified influenza virus with other respiratory manifestations, J11.00 — Influenza due to unidentified influenza virus with unspecified type of pneumonia, +108 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Opportunistic Infections) for risk-adjusted payment.

A31.0 — Pulmonary mycobacterial infection, A31.2 — Disseminated mycobacterium avium-intracellulare complex (DMAC), B25.0 — Cytomegaloviral pneumonitis, B25.1 — Cytomegaloviral hepatitis, B25.2 — Cytomegaloviral pancreatitis, B25.8 — Other cytomegaloviral diseases, B25.9 — Cytomegaloviral disease, unspecified, B37.1 — Pulmonary candidiasis, B37.7 — Candidal sepsis, B37.81 — Candidal esophagitis, B44.1 — Other pulmonary aspergillosis, B44.2 — Tonsillar aspergillosis, B44.7 — Disseminated aspergillosis, B44.89 — Other forms of aspergillosis, B44.9 — Aspergillosis, unspecified, B45.0 — Pulmonary cryptococcosis, B45.1 — Cerebral cryptococcosis, B45.2 — Cutaneous cryptococcosis, B45.3 — Osseous cryptococcosis, B45.7 — Disseminated cryptococcosis, +16 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Other specified and unspecified lower respiratory disease, Fungal infections).

B42.7 — Disseminated sporotrichosis, B42.81 — Cerebral sporotrichosis, B42.82 — Sporotrichosis arthritis, B42.89 — Other forms of sporotrichosis, B42.9 — Sporotrichosis, unspecified, B43.0 — Cutaneous chromomycosis, B43.1 — Pheomycotic brain abscess, B43.2 — Subcutaneous pheomycotic abscess and cyst, B43.8 — Other forms of chromomycosis, B43.9 — Chromomycosis, unspecified, B44.1 — Other pulmonary aspergillosis, B44.2 — Tonsillar aspergillosis, B44.7 — Disseminated aspergillosis, B44.81 — Allergic bronchopulmonary aspergillosis, B44.89 — Other forms of aspergillosis, B44.9 — Aspergillosis, unspecified, B45.0 — Pulmonary cryptococcosis, B45.1 — Cerebral cryptococcosis, B45.2 — Cutaneous cryptococcosis, B45.3 — Osseous cryptococcosis, +157 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, HIV Screening Test

Contextual Map

Every relationship of B44.0 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 B44.0 with these 4 related codes in Claim Check

Hierarchy

• A00-B99 — Chapter 1: Certain Infectious and Parasitic Diseases (A00-B99) (A00-B99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B35-B49 — Mycoses[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• J17 — Pneumonia in diseases classified elsewhere[Excludes1]: “pneumonia in aspergillosis (B44.0-B44.1)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• J82 — Pulmonary eosinophilia, not elsewhere classified[Excludes2](via B44.-): “pulmonary eosinophilia due to aspergillosis (B44.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code First instructions

• M01 — Direct infections of joint in infectious and parasitic diseases classified elsewhere[Code First](via B44.-): “mycoses (B35-B49)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code Also instructions

• J4B — Pulmonary mycetoma[Code Also](via B44.-): “aspergillosis (B44.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• RSP016 — Other specified and unspecified lower respiratory disease[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
• INF004 — Fungal infections[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 6 — Opportunistic Infections [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• MCC — Major Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (MCC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 177 — RESPIRATORY INFECTIONS AND INFLAMMATIONS WITH MCC[MS-DRG]: “RESPIRATORY INFECTIONS AND INFLAMMATIONS WITH MCC (MDC 04)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 178 — RESPIRATORY INFECTIONS AND INFLAMMATIONS WITH CC[MS-DRG]: “RESPIRATORY INFECTIONS AND INFLAMMATIONS WITH CC (MDC 04)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 179 — RESPIRATORY INFECTIONS AND INFLAMMATIONS WITHOUT CC/MCC[MS-DRG]: “RESPIRATORY INFECTIONS AND INFLAMMATIONS WITHOUT CC/MCC (MDC 04)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 04 — Diseases and Disorders of the Respiratory System[MDC crossing]: “Diseases and Disorders of the Respiratory System — 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. 3,998 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Aspergillosis (with pneumonia), pulmonary NEC, invasive[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• B44 — Aspergillosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B44.1 — Other pulmonary aspergillosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B44.2 — Tonsillar aspergillosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B44.7 — Disseminated aspergillosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B44.8 — Other forms of aspergillosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B44.81 — Allergic bronchopulmonary aspergillosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B44.89 — Other forms of aspergillosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B44.9 — Aspergillosis, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history (8)

• FY2027 — Code Also note will be added[Change history]— CMS release files (code change ledger) · icd10cm-fy2027
• and 7 more

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 FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 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 — v43 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 structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder 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.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to B44.0 in its code family, with their registry titles.

• B44 — Aspergillosis
• B44.1 — Other pulmonary aspergillosis
• B44.2 — Tonsillar aspergillosis
• B44.7 — Disseminated aspergillosis
• B44.8 — Other forms of aspergillosis
• B44.81 — Allergic bronchopulmonary aspergillosis
• B44.89 — Other forms of aspergillosis
• B44.9 — Aspergillosis, unspecified

View all codes in the B44 family