2026 ICD-10-CM Diagnosis Code B78.9Strongyloidiasis, unspecified

ICD-10-CM Codes›A00–B99›B65-B83›B78

ICD-10-CM B78.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B78.9 is a billable ICD-10-CM diagnosis code for strongyloidiasis, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392, 974 through 976. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 16 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
B78.9
Billable Status
Yes — Valid for Submission
Code Describes
Strongyloidiasis, unspecified
Short Description
Strongyloidiasis, unspecified
Same as the full description in the CMS dataset.
Parent Code
B78
Strongyloidiasis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB65-B83Helminthiases
CategoryB78Strongyloidiasis
This CodeB78.9Strongyloidiasis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cerebrospinal nematodiasis
  • Disease caused by Strongyloidea
  • Gastritis caused by Strongyloides stercoralis
  • Glomerular disease due to infectious disease
  • Glomerular disease due to parasitic disease
  • Glomerular disorder due to Strongyloides infection
  • Infection by Strongyloides
  • Infection by Strongyloides canis
  • Infection by Strongyloides cebus
  • Infection by Strongyloides fulleborni
  • Infection by Strongyloides papillosus
  • Infection by Strongyloides ransomi
  • Infection by Strongyloides ratti
  • Infection by Strongyloides simiae
  • Infection by Strongyloides stercoralis
  • Infection by Strongyloides tumefaciens
  • Infection by Strongyloides westeri
  • Infection caused by Strongyloides co-occurrent with human immunodeficiency virus infection
  • Massive strongyloidiasis
  • Strongyloides stercoralis meningitis
  • Strongyloidiasis with AIDS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

  • Strongyloidiasis

    infection with nematodes of the genus strongyloides. the presence of larvae may produce pneumonitis and the presence of adult worms in the intestine could lead to moderate to severe diarrhea.

  • Strongyloides

    a genus of parasitic nematodes widely distributed as intestinal parasites of mammals.

  • Strongyloidiasis

    an infection that is caused by nematodes of the genus strongyloides, most commonly strongyloides stercoralis, which is a soil-transmitted helminth, and which is characterized by a variety of gastrointestinal, dermatologic, and, occasionally, pulmonary manifestations. the worm's autoinfective life cycle can lead to hyper-infection and life-threatening dissemination in immunocompromised hosts decades after initial infection.

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 B78.9 to ICD-9-CMHistory

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

ICD-9-CM
127.2 Strongyloidiasis
Approximate The match is approximate rather than exact.

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 B78.9Overview

What is the ICD-10 code for strongyloidiasis, unspecified?

The ICD-10-CM code for strongyloidiasis, unspecified is B78.9 (sometimes written as B789). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is B78.9 (Strongyloidiasis) a billable code?

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

What MS-DRG does B78.9 group to?

When strongyloidiasis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, 974, 975, 976, with relative weights from 0.7796 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

Is B78.9 a CC or MCC?

CMS lists B78.9 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 16 closely related codes in its exclusion list.

What is the ICD-9 equivalent of B78.9?

Under the General Equivalence Mappings, strongyloidiasis, unspecified converts to ICD-9-CM 127.2 (strongyloidiasis). The mapping is approximate, so confirm the match fits the documentation.