2026 ICD-10-CM Diagnosis Code K40.90Unilateral inguinal hernia, without obstruction or gangrene, not specified as recurrent

ICD-10-CM Codes›K00–K95›K40-K46›K40

ICD-10-CM K40.90
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K40.90 is a billable ICD-10-CM diagnosis code for unilateral inguinal hernia, without obstruction or gangrene, not specified as recurrent. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 393 through 395. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Abdominal hernia.

Code Identity

ICD-10-CM Code
K40.90
Billable Status
Yes — Valid for Submission
Code Describes
Unilateral inguinal hernia, without obstruction or gangrene, not specified as recurrent
Short Description
Unil inguinal hernia, w/o obst or gangr, not spcf as recur
Parent Code
K40.9
Unilateral inguinal hernia, without obstruction or gangrene

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK40-K46Hernia
CategoryK40Inguinal hernia
This CodeK40.90Unilateral inguinal hernia, without obstruction or gangrene, not specified as recurrent

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Branchial dysplasia, intellectual disability, inguinal hernia syndrome
  • Bubonocele
  • Congenital inguinal hernia
  • Developmental malformation of branchial arch
  • Direct inguinal hernia
  • Funicular indirect inguinal hernia
  • Herniation descends to scrotum
  • Indirect inguinal hernia
  • Indirect left inguinal hernia
  • Indirect right inguinal hernia
  • Inguinal hernia
  • Interstitial hernia
  • Labial hernia
  • Left direct inguinal hernia
  • Left inguinal hernia
  • Marfanoid habitus, inguinal hernia, advanced bone age syndrome
  • Marfanoid physique
  • Properitoneal inguinal hernia
  • Protrusion of bowel into inguinal canal
  • Retroperitoneal hernia
  • Right direct inguinal hernia
  • Right inguinal hernia
  • Scrotal hernia
  • Sliding inguinal hernia

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Inguinal hernia NOS
  • Unilateral inguinal hernia NOS

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.

    • Hernia, hernial(acquired) (recurrent)
      • inguinal (direct) (external) (funicular) (indirect) (internal) (oblique) (scrotal) (sliding)
    • Hernia, hernial(acquired) (recurrent)
      • inguinal (direct) (external) (funicular) (indirect) (internal) (oblique) (scrotal) (sliding)
        • not specified as recurrent
    • Hernia, hernial(acquired) (recurrent)
      • inguinal (direct) (external) (funicular) (indirect) (internal) (oblique) (scrotal) (sliding)
        • unilateral
    • Hernia, hernial(acquired) (recurrent)
      • inguinal (direct) (external) (funicular) (indirect) (internal) (oblique) (scrotal) (sliding)
        • unilateral
          • not specified as recurrent

Clinical ClassificationClinical

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

CCSR DIG010
Abdominal hernia
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Scrotal Hernia

    the protrusion of abdominal cavity contents into the scrotal sac.

  • Direct Inguinal Hernia

    a protrusion of the abdominal cavity contents into the inguinal canal through the superficial inguinal ring.

  • Incarcerated Inguinal Hernia

    the trapping of bowel or omentum inside the inguinal canal that cannot be reduced, resulting in inflammation, pain, nausea, and possible bowel obstruction.

  • Indirect Inguinal Hernia

    a protrusion of the abdominal cavity contents into the inguinal canal through the deep and superficial inguinal rings.

  • Inguinal Hernia

    the protrusion of a sac-like structure containing fibroadipose tissue through an abnormal opening in the inguinal region.

  • Inguinal Hernia without Mention of Obstruction or Gangrene

    the protrusion of abdominal cavity contents through the inguinal canal, without mention of obstruction or necrosis of the herniated contents.

Patient EducationClinical

Hernia

A hernia happens when part of an internal organ or tissue bulges through a weak area of muscle. Most hernias are in the abdomen.

Read the full article at MedlinePlus

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

Convert K40.90 to ICD-9-CMHistory

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

ICD-9-CM
550.90 Unilat inguinal hernia
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 K40.90Overview

Is K40.90 (Unilateral inguinal hernia, without obstruction or gangrene) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unilateral inguinal hernia, without obstruction or gangrene, not specified as recurrent on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K40.90 group to?

When unilateral inguinal hernia, without obstruction or gangrene, not specified as recurrent is the principal diagnosis on an inpatient stay, it groups to MS-DRG 393, 394, 395, with relative weights from 0.6490 to 1.5993 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K40.90?

Under the General Equivalence Mappings, unilateral inguinal hernia, without obstruction or gangrene, not specified as recurrent converts to ICD-9-CM 550.90 (unilat inguinal hernia). 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.