2026 ICD-10-CM Diagnosis Code K73.1Chronic lobular hepatitis, not elsewhere classified

ICD-10-CM Codes›K00–K95›K70-K77›K73

ICD-10-CM K73.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K73.1 is a billable ICD-10-CM diagnosis code for chronic lobular hepatitis, not elsewhere classified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 441 through 443. Coders also document this condition as chronic lobular hepatitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Noninfectious hepatitis.

Code Identity

ICD-10-CM Code
K73.1
Billable Status
Yes — Valid for Submission
Code Describes
Chronic lobular hepatitis, not elsewhere classified
Short Description
Chronic lobular hepatitis, not elsewhere classified
Same as the full description in the CMS dataset.
Parent Code
K73
Chronic hepatitis, not elsewhere classified

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK70-K77Diseases of liver
CategoryK73Chronic hepatitis, not elsewhere classified
This CodeK73.1Chronic lobular hepatitis, not elsewhere classified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Chronic lobular hepatitis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

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

    • Hepatitis
      • chronic
        • lobular NEC

Clinical ClassificationClinical

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

CCSR DIG023
Noninfectious hepatitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Hepatitis

Hepatitis is inflammation of the liver. Inflammation is swelling that happens when tissues of the body are injured or infected. It can damage your liver. This swelling and damage can affect how well your liver functions.

The full article covers:

  • What is hepatitis?
  • What causes hepatitis?
  • How is viral hepatitis spread?
  • Who is at risk for hepatitis?
  • What are the symptoms of hepatitis?
  • What other problems can hepatitis cause?
  • How is hepatitis diagnosed?
  • What are the treatments for hepatitis?

Read the full article at MedlinePlus

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

Convert K73.1 to ICD-9-CMHistory

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

ICD-9-CM
571.49 Chronic hepatitis NEC
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 K73.1Overview

Is K73.1 (Chronic hepatitis, not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report chronic lobular hepatitis, not elsewhere classified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K73.1 group to?

When chronic lobular hepatitis, not elsewhere classified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 441, 442, 443, with relative weights from 0.6997 to 1.7947 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K73.1?

Under the General Equivalence Mappings, chronic lobular hepatitis, not elsewhere classified converts to ICD-9-CM 571.49 (chronic hepatitis NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.