2027 ICD-10-CM Diagnosis Code J15.9Unspecified bacterial pneumonia

ICD-10-CM Codes›J00–J99›J09-J18›J15

ICD-10-CM J15.9
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

J15.9 is a billable ICD-10-CM diagnosis code for unspecified bacterial pneumonia. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 193 through 195, 791, 793, 974 through 976. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 129 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Pneumonia (except that caused by tuberculosis).

Code Identity

ICD-10-CM Code
J15.9
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified bacterial pneumonia
Short Description
Unspecified bacterial pneumonia
Same as the full description in the CMS dataset.
Parent Code
J15
Bacterial pneumonia, not elsewhere classified

Code Classification

ChapterJ00–J99Diseases of the respiratory system
SectionJ09-J18Influenza and pneumonia
CategoryJ15Bacterial pneumonia, not elsewhere classified
This CodeJ15.9Unspecified bacterial pneumonia

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bacterial pneumonia
  • Bacterial pneumonia co-occurrent with human immunodeficiency virus infection
  • Bacterial pneumonia with AIDS
  • Bronchopneumonia caused by bacteria
  • Disorder of respiratory system co-occurrent with human immunodeficiency virus infection
  • Healthcare associated bacterial pneumonia
  • Hospital acquired pneumonia
  • Pneumonia caused by aerobic bacteria
  • Pneumonia with AIDS
  • Recurrent bacterial pneumonia
  • Recurrent bacterial pneumonia co-occurrent with human immunodeficiency virus infection
  • Recurrent lower respiratory tract infection
  • Recurrent pneumonia
  • Respiratory disorder with AIDS
  • Secondary bacterial pneumonia

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to J15.9: its own notes plus those printed at J15, block J09-J18, and Chapter 10. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From J15 Bacterial pneumonia, not elsewhere classified applies to 14 codes
  • bronchopneumonia due to bacteria other than S. pneumoniae and H. influenzae

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Pneumonia due to gram-positive bacteria

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From J15 Bacterial pneumonia, not elsewhere classified applies to 14 codes
  • chlamydial pneumonia (J16.0)
  • congenital pneumonia (P23.-)
  • Legionnaires' disease (A48.1)
  • spirochetal pneumonia (A69.8)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block J09-J18 Influenza and pneumonia applies to 53 codes
  • allergic or eosinophilic pneumonia (J82)
  • aspiration pneumonia NOS (J69.0)
  • meconium pneumonia (P24.01)
  • neonatal aspiration pneumonia (P24.-)
  • pneumonia due to solids and liquids (J69.-)
  • congenital pneumonia (P23.9)
  • lipid pneumonia (J69.1)
  • rheumatic pneumonia (I00)
  • ventilator associated pneumonia (J95.851)
From Chapter 10 (J00-J99) Diseases of the respiratory system applies to 366 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • smoke inhalation (T59.81-)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Code First

The underlying condition named in the note is sequenced before this code.

From J15 Bacterial pneumonia, not elsewhere classified applies to 14 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Block J09-J18 Influenza and pneumonia applies to 53 codes
  • code, if applicable, to identify resistance to antimicrobial drugs (Z16.-)
From Chapter 10 (J00-J99) Diseases of the respiratory system applies to 366 codes
  • code, where applicable, to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • exposure to tobacco smoke in the perinatal period (P96.81)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From J15 Bacterial pneumonia, not elsewhere classified applies to 14 codes
  • if applicable, any associated condition such as:
  • abscess (J85.1)
  • aspiration pneumonia (J69.-)

Notes

General instructions on how these codes are used.

From Chapter 10 (J00-J99) Diseases of the respiratory system applies to 366 codes
  • When a respiratory condition is described as occurring in more than one site and is not specifically indexed, it should be classified to the lower anatomic site (e.g. tracheobronchitis to bronchitis in J40).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name J15.9, its category, or a range that includes it.

Use Additional Code 1

These codes say to use an additional code from the note, and J15.9 is one of the codes named.

  • J95.89 Other postprocedural complications and disorders of respiratory system, not elsewhere classified
    bacterial or viral pneumonia (J12-J18) names J12-J18, which includes this code

Code Also 2

These codes say J15.9 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • D81.82 Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]
    pneumonia (J12-J18) names J12-J18, which includes this code
  • J69 Pneumonitis due to solids and liquids
    bacterial pneumonia (J13-J15.-) names J13-J15, which includes this code

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 INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR RSP002
Pneumonia (except that caused by tuberculosis)
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Pneumonia, Bacterial

    inflammation of the lung parenchyma that is caused by bacterial infections.

Patient EducationClinical

Pneumonia

Pneumonia is an infection in one or both of your lungs. It causes the air sacs of your lungs to fill up with fluid or pus. Pneumonia can range from mild to severe, depending on what caused it, your age, and your overall health.

The full article covers:

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

Read the full article at MedlinePlus

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

Convert J15.9 to ICD-9-CMHistory

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

ICD-9-CM
482.9 Bacterial pneumonia 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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About J15.9Overview

What is the ICD-10 code for unspecified bacterial pneumonia?

The ICD-10-CM code for unspecified bacterial pneumonia is J15.9 (sometimes written as J159). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is J15.9 (Bacterial pneumonia, not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified bacterial pneumonia on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does J15.9 group to?

When unspecified bacterial pneumonia is the principal diagnosis on an inpatient stay, it groups to MS-DRG 195, 793, 791, 193, 194, 974, 976, 975, with relative weights from 0.6062 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.

Is J15.9 a CC or MCC?

CMS lists J15.9 as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 129 closely related codes in its exclusion list.

Can J15.9 be reported with J16.0?

Not as a rule. The Excludes1 note at J15, which applies to J15.9, lists "chlamydial pneumonia (J16.0)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).