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B77.81 ICD-10-CM Code: Ascariasis pneumonia

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

Coding at a Glance

Tabular directives
2 inclusion terms

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 v43, Appendix B.

  • MS-DRG 391 — ESOPHAGITIS, GASTROENTERITIS AND MISCELLANEOUS DIGESTIVE DISORDERS WITH MCC (MDC 06)
  • MS-DRG 392 — ESOPHAGITIS, GASTROENTERITIS AND MISCELLANEOUS DIGESTIVE DISORDERS WITHOUT MCC (MDC 06)

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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for B77.81 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 B77.81 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • ascaridiasis
  • roundworm infection

Source: inherited from B77

Code Overview

Ascariasis pneumonia is a billable ICD-10-CM diagnosis code (B77.81).

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

Indexed Clinical Terms (3)

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.

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 B77.81 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 B77.-).

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

Referenced by 2 Code First instructions across 2 chapters: H94.0 — Acoustic neuritis in infectious and parasitic diseases classified elsewhere (via B77.-), K67 — Disorders of peritoneum in infectious diseases classified elsewhere (via B77.-).

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.

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 145 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 391 (MDC 06), DRG 392 (MDC 06).

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

Clinical classification (AHRQ CCSR):RSP002 — Pneumonia (except that caused by tuberculosis) (default); INF009 — Parasitic, other specified and unspecified 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.

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, B44.0 — Invasive pulmonary aspergillosis, B58.3 — Pulmonary toxoplasmosis, B59 — Pneumocystosis, B67.1 — Echinococcus granulosus infection of lung, B77.0 — Ascariasis with intestinal complications, B77.89 — Ascariasis with other complications, B77.9 — Ascariasis, unspecified, B78.0 — Intestinal strongyloidiasis, B78.7 — Disseminated strongyloidiasis, B78.9 — Strongyloidiasis, unspecified, B79 — Trichuriasis, B80 — Enterobiasis, B81.0 — Anisakiasis, B81.1 — Intestinal capillariasis, B81.2 — Trichostrongyliasis, +124 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Pneumonia (except that caused by tuberculosis), Parasitic, other specified and unspecified infections).

B74.3 — Loiasis, B74.4 — Mansonelliasis, B74.8 — Other filariases, B74.9 — Filariasis, unspecified, B75 — Trichinellosis, B76.0 — Ancylostomiasis, B76.1 — Necatoriasis, B76.8 — Other hookworm diseases, B76.9 — Hookworm disease, unspecified, B77.0 — Ascariasis with intestinal complications, B77.89 — Ascariasis with other complications, B77.9 — Ascariasis, unspecified, B78.0 — Intestinal strongyloidiasis, B78.1 — Cutaneous strongyloidiasis, B78.7 — Disseminated strongyloidiasis, B78.9 — Strongyloidiasis, unspecified, B79 — Trichuriasis, B80 — Enterobiasis, B81.0 — Anisakiasis, B81.1 — Intestinal capillariasis, +302 more

Same Index main term, other category

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

B38.0 — Acute pulmonary coccidioidomycosis (in, coccidioidomycosis, acute), B38.1 — Chronic pulmonary coccidioidomycosis (in, coccidioidomycosis, chronic), B38.2 — Pulmonary coccidioidomycosis, unspecified (in, coccidioidomycosis), B39.0 — Acute pulmonary histoplasmosis capsulati (in, histoplasmosis, acute), B39.1 — Chronic pulmonary histoplasmosis capsulati (in, histoplasmosis, chronic), B39.2 — Pulmonary histoplasmosis capsulati, unspecified (in, histoplasmosis), B44.9 — Aspergillosis, unspecified (in, aspergillosis), B58.3 — Pulmonary toxoplasmosis (in, toxoplasmosis), B59 — Pneumocystosis (plasma cell), B65.9 — Schistosomiasis, unspecified (in, schistosomiasis), B99 — Other and unspecified infectious diseases (postinfectional NEC), I00 — Rheumatic fever without heart involvement (rheumatic), J12.0 — Adenoviral pneumonia (adenoviral), J12.1 — Respiratory syncytial virus pneumonia (respiratory syncytial virus), J12.2 — Parainfluenza virus pneumonia (parainfluenza virus), J12.3 — Human metapneumovirus pneumonia (human metapneumovirus), J12.81 — Pneumonia due to SARS-associated coronavirus (SARS-associated coronavirus), J12.82 — Pneumonia due to coronavirus disease 2019 (COVID-19), J12.89 — Other viral pneumonia (specified NEC, virus NEC), J12.9 — Viral pneumonia, unspecified (viral, virus), +82 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, Fecal Occult Blood Test (FOBT)

Contextual Map

Every relationship of B77.81 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 B77.81 with these 4 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Referenced by Code First instructions

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 06 — Diseases and Disorders of the Digestive System[MDC crossing]: “Diseases and Disorders of the Digestive 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. 5,744 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Ascariasis, with, pneumonia, pneumonitis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved), Ascaris[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved), in (due to), ascariasis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

Change history

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

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
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

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. "B77.81 — Ascariasis pneumonia." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/b77.81-ascariasis-pneumonia

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Ascariasis pneumonia

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), 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 B77.81 in its code family, with their registry titles.

View all codes in the B77 family