2026 ICD-10-CM Diagnosis Code I38Endocarditis, valve unspecified

ICD-10-CM Codes›I00–I99›I30-I5A›I38

ICD-10-CM I38
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I38 is a billable ICD-10-CM diagnosis code for endocarditis, valve unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 306 through 307. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Endocarditis and endocardial disease.

Code Identity

ICD-10-CM Code
I38
Billable Status
Yes — Valid for Submission
Code Describes
Endocarditis, valve unspecified
Chapter
I30-I5A
Other forms of heart disease

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI38Endocarditis, valve unspecified
This CodeI38Endocarditis, valve unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormality of right atrioventricular valve in double inlet ventricle
  • Abnormality of truncal valve cusp
  • Abscess of left atrioventricular valve
  • Abscess of right atrioventricular valve
  • Acquired abnormality of common atrioventricular valve following procedure
  • Acquired abnormality of common atrioventricular valve following repair of biventricular atrioventricular connection
  • Acquired abnormality of congenital malformed heart valve following repair
  • Acquired abnormality of left atrioventricular valve
  • Acquired abnormality of left atrioventricular valve following repair of double inlet ventricle
  • Acquired abnormality of right atrioventricular valve
  • Acquired abnormality of right atrioventricular valve following repair of double inlet ventricle
  • Acquired common atrioventricular valve regurgitation following procedure
  • Acquired regurgitation of common atrioventricular valve following repair of biventricular connection
  • Acquired regurgitation of left ventricular component of common atrioventricular valve following repair of biventricular connection
  • Acquired regurgitation of right ventricular component of common atrioventricular valve following repair of biventricular connection
  • Acquired stenosis of common atrioventricular valve following repair of biventricular connection
  • Acquired stenosis of left ventricular component of common atrioventricular valve following repair of biventricular connection
  • Acquired stenosis of right ventricular component of common atrioventricular valve following repair of biventricular connection
  • Acquired ventricular septal defect
  • Atrial fibrillation due to heart valve disorder
  • Atrioventricular block due to endocarditis
  • Calcification of common atrioventricular valve
  • Calcification of left atrioventricular valve
  • Calcification of right atrioventricular valve
  • Calcification of truncal valve
  • Cardiac valve prolapse
  • Cardiovascular fistula due to endocarditis
  • Chronic endocarditis
  • Chronic valvulitis
  • Common atrioventricular valve stenosis
  • Congestive heart failure due to valvular disease
  • Culture-negative endocarditis
  • Dilatation of left atrioventricular valve in double inlet ventricle
  • Dilatation of left atrioventricular valve annulus
  • Dilatation of right atrioventricular valve annulus
  • Dilation of right atrioventricular valve in double inlet ventricle
  • Disorder of atrioventricular valve
  • Disorder of cardiac valve following procedure
  • Disorder of left atrioventricular valve
  • Disorder of pulmonary valve prosthesis
  • Disorder of right atrioventricular valve
  • Endocarditis
  • Endocarditis as complication of procedure
  • Endocarditis associated with another disorder
  • Endocarditis of prosthetic pulmonary valve
  • Heart failure with normal ejection fraction
  • Heart failure with reduced ejection fraction
  • Heart failure with reduced ejection fraction due to heart valve disease
  • Heart valve disorder
  • Heart valve regurgitation
  • Heart valve stenosis and regurgitation
  • Inflammation associated with cardiac implant
  • Left ventricular failure with normal ejection fraction due to valvular heart disease
  • Mitral valve disorder in pregnancy
  • Myxoid transformation of cardiac valve
  • Myxomatous degeneration of left atrioventricular valve leaflet
  • Myxomatous degeneration of right atrioventricular valve leaflet
  • Nonbacterial thrombotic endocarditis
  • Noninfective endocarditis
  • Non-rheumatic heart valve disorder
  • Paroxysmal atrial fibrillation
  • Paroxysmal atrial fibrillation due to heart valve disorder
  • Perforation of left atrioventricular valve leaflet
  • Perforation of right atrioventricular valve leaflet
  • Perforation of truncal valve cusp
  • Periendocarditis due to infection
  • Permanent atrial fibrillation
  • Permanent atrial fibrillation due to heart valve disorder
  • Persistent atrial fibrillation
  • Persistent atrial fibrillation due to heart valve disorder
  • Postcapillary pulmonary hypertension
  • Postprocedural common atrioventricular valvar stenosis
  • Pulmonary hypertension due to left heart disease
  • Pulmonary hypertension due to left-sided valvular heart disease
  • Regurgitation of atrioventricular valve
  • Regurgitation of common atrioventricular valve
  • Regurgitation of left atrioventricular valve
  • Regurgitation of right atrioventricular valve
  • Right ventricular failure due to valvular heart disease
  • Rupture of left atrioventricular valve leaflet
  • Rupture of right atrioventricular valve leaflet
  • Rupture of truncal valve cusp
  • Stenosis of truncal valve following procedure
  • Thrombosis of common atrioventricular valve
  • Thrombosis of left atrioventricular valve
  • Thrombosis of right atrioventricular valve
  • Thrombosis of truncal valve
  • Truncal valve abnormality
  • Truncal valve stenosis
  • Valvular endocarditis
  • Valvular regurgitation
  • Valvular sclerosis
  • Vegetation of heart
  • Vegetative endocarditis
  • Vegetative endocarditis without infection
  • Ventricular septal defect due to and following infective endocarditis

Tabular List NotesGuidance

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

Includes

  • endocarditis (chronic) NOS
  • valvular incompetence NOS
  • valvular insufficiency NOS
  • valvular regurgitation NOS
  • valvular stenosis NOS
  • valvulitis (chronic) NOS

Type 1 Excludes

  • congenital insufficiency of cardiac valve NOS Q24.8
  • congenital stenosis of cardiac valve NOS Q24.8
  • endocardial fibroelastosis I42.4
  • endocarditis specified as rheumatic I09.1

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

  • - Stricture - See Also: Stenosis;

    • - heart - See Also: Disease, heart;

      • - valve - See Also: Endocarditis; - I38

External Cause of Injuries IndexGuidance

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

    • Disease, diseased
      • valve, valvular
    • Endocarditis(chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
    • Endocarditis(chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
      • arteriosclerotic
    • Hypertrophy, hypertrophic
      • heart (idiopathic)
        • valve
    • Insufficiency, insufficient
      • valve, valvular (heart)
    • Stenosis, stenotic(cicatricial)
      • heart valve
    • Stenosis, stenotic(cicatricial)
      • valve (cardiac) (heart)
    • Stricture
      • heart
        • valve

Clinical ClassificationClinical

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

CCSR CIR004
Endocarditis and endocardial disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Endocarditis

    inflammation of the inner lining of the heart (endocardium), the continuous membrane lining the four chambers and heart valves. it is often caused by microorganisms including bacteria, viruses, fungi, and rickettsiae. left untreated, endocarditis can damage heart valves and become life-threatening.

  • Endocarditis, Bacterial

    inflammation of the endocardium caused by bacteria that entered the bloodstream. the strains of bacteria vary with predisposing factors, such as congenital heart defects; heart valve diseases; heart valve prosthesis implantation; or intravenous drug use.

  • Endocarditis, Non-Infective

    formation of a non-infectious thrombus, referred to as vegetation, on previously undamaged endocardium. it usually occurs as a complication of connective-tissue diseases and cancers because of the associated hypercoagulable state (see thrombophilia).

  • Endocarditis, Subacute Bacterial

    endocardium infection that is usually caused by streptococcus. subacute infective endocarditis evolves over weeks and months with modest toxicity and rare metastatic infection.

  • Hypereosinophilic Syndrome

    a heterogeneous group of disorders with the common feature of prolonged eosinophilia of unknown cause and associated organ system dysfunction, including the heart, central nervous system, kidneys, lungs, gastrointestinal tract, and skin. there is a massive increase in the number of eosinophils in the blood, mimicking leukemia, and extensive eosinophilic infiltration of the various organs.

  • Rat-Bite Fever

    a syndrome characterized by recurring fever, rash, and arthralgias occurring days to weeks after a rat bite. the causative agents are either streptobacillus moniliformis or spirillum minus.

  • Eosinophils

    granular leukocytes with a nucleus that usually has two lobes connected by a slender thread of chromatin, and cytoplasm containing coarse, round granules that are uniform in size and stainable by eosin.

Patient EducationClinical

Endocarditis

Endocarditis is sometimes called infective endocarditis. It's a rare but life-threatening inflammation of the lining inside your heart's chambers and valves (the endocardium).

The full article covers:

  • What is endocarditis?
  • What causes endocarditis?
  • Who is more likely to develop endocarditis?
  • What are the symptoms of endocarditis?
  • What other problems can endocarditis cause?
  • How is endocarditis diagnosed?
  • What are the treatments for endocarditis?
  • Can endocarditis be prevented?

Read the full article at MedlinePlus

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

Convert I38 to ICD-9-CMHistory

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

ICD-9-CM
424.90 Endocarditis NOS
Approximate The match is approximate rather than exact.
ICD-9-CM
424.99 Endocarditis 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 I38Overview

Is I38 (Endocarditis, valve unspecified) a billable code?

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

What MS-DRG does I38 group to?

When endocarditis, valve unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 306, 307, with relative weights from 0.9132 to 1.5758 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I38?

Under the General Equivalence Mappings, endocarditis, valve unspecified converts to ICD-9-CM 424.90 (endocarditis NOS) and 424.99 (endocarditis 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.