2026 ICD-10-CM Diagnosis Code B74.9Filariasis, unspecified

ICD-10-CM Codes›A00–B99›B65-B83›B74

ICD-10-CM B74.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B74.9 is a billable ICD-10-CM diagnosis code for filariasis, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 867 through 869. Coders also document this condition as disease caused by Filarioidea. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
B74.9
Billable Status
Yes — Valid for Submission
Code Describes
Filariasis, unspecified
Short Description
Filariasis, unspecified
Same as the full description in the CMS dataset.
Parent Code
B74
Filariasis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB65-B83Helminthiases
CategoryB74Filariasis
This CodeB74.9Filariasis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disease caused by Filarioidea
  • Filarial abscess
  • Filarial infection of conjunctiva
  • Lymphatic filariasis
  • Parasitic conjunctivitis
  • Pulmonary filariasis
  • Pulmonary nematodiasis
  • Serous cavity filariasis
  • Subcutaneous filariasis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

  • - Mumu - See Also: Infestation, filarial; - B74.9

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Arthritis, arthritic(acute) (chronic) (nonpyogenic) (subacute)
      • chylous (filarial)
    • Arthritis, arthritic(acute) (chronic) (nonpyogenic) (subacute)
      • due to or associated with
        • filariasis NOS
    • Chylocele(nonfilarial)
      • filarial
    • Chylocele(nonfilarial)
      • tunica vaginalis
        • filarial
    • Chylothorax(nonfilarial)
      • filarial
    • Conjunctivitis(staphylococcal) (streptococcal) NOS
      • due to
        • filariasis
    • Conjunctivitis(staphylococcal) (streptococcal) NOS
      • in (due to)
        • filariasis
    • Conjunctivitis(staphylococcal) (streptococcal) NOS
      • parasitic
        • filariasis
    • Epididymitis(acute) (nonvenereal) (recurrent) (residual)
      • filarial
    • Hydrothorax(double) (pleura)
      • chylous (nonfilarial)
        • filarial
    • Infestation
      • filarial
    • Infestation
      • filarial
        • conjunctiva
    • Mumu
    • Orchitis(gangrenous) (nonspecific) (septic) (suppurative)
      • filarial

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Elephantiasis, Filarial

    parasitic infestation of the human lymphatic system by wuchereria bancrofti or brugia malayi. it is also called lymphatic filariasis.

  • Filariasis

    infections with nematodes of the superfamily filarioidea. the presence of living worms in the body is mainly asymptomatic but the death of adult worms leads to granulomatous inflammation and permanent fibrosis. organisms of the genus elaeophora infect wild elk and domestic sheep causing ischemic necrosis of the brain, blindness, and dermatosis of the face.

  • Loiasis

    a parasitic infection caused by the nematode loa loa. the vector in the transmission of this infection is the horsefly (tabanus) or the deerfly or mango fly (chrysops). the larvae may be seen just beneath the skin or passing through the conjunctiva. eye lesions are not uncommon. the disease is generally mild and painless.

  • Filarioidea

    a superfamily of nematodes of the order spirurida. members possess a filiform body and a mouth surrounded by papillae.

  • Filariasis

    infection by filarial worms.

  • Lymphatic Filariasis|Elephantiasis

    a clinical disorder that is caused by obstruction of the lymphatic system years after filarial infection. it is characterized by painful and profound lymphedema, resulting in significant swelling (elephantiasis) of extremities and genitals.

Patient EducationClinical

Parasitic Diseases

Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert B74.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
125.9 Filariasis NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About B74.9Overview

Is B74.9 (Filariasis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report filariasis, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does B74.9 group to?

When filariasis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 868, 869, with relative weights from 0.7297 to 2.0932 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B74.9?

Under the General Equivalence Mappings, filariasis, unspecified converts to ICD-9-CM 125.9 (filariasis NOS). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.