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ICD-10-CM 2027 diagnosis code

J18.9Pneumonia, unspecified organism

✓ Billable / specificMCC — major complication/comorbidity

J18.9 is a valid, billable ICD-10-CM code for pneumonia, unspecified organism. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Pneumonia, ICD-10 code for Lung infection.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About J18.9

J18.9 is the ICD-10-CM diagnosis code for pneumonia, unspecified organism. It belongs to category J18 (pneumonia, unspecified organism), block J09-J18 (influenza and pneumonia) and chapter 10 (diseases of the respiratory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within J18, choose J18.9 (Pneumonia, unspecified organism) only when documentation doesn't support a more specific option: Bronchopneumonia, unspecified organism (J18.0), Lobar pneumonia, unspecified organism (J18.1), Hypostatic pneumonia, unspecified organism (J18.2) and other pneumonia, unspecified organism (J18.8).

Code first: , if applicable, associated influenza (J09.X1, J10.0-, J11.0-).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 193 (Simple Pneumonia and Pleurisy with MCC, relative weight 1.2825), DRG 194 (Simple Pneumonia and Pleurisy with CC, relative weight 0.7888), DRG 195 (Simple Pneumonia and Pleurisy without CC/MCC, relative weight 0.6063), DRG 791 (Prematurity with Major Problems, relative weight 4.1075), DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), DRG 974 (HIV with Major Related Condition with MCC, relative weight 3.0506) and 2 more, in MDC 04 (Diseases and Disorders of the Respiratory System), MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period) and MDC 25 (Human Immunodeficiency Virus Infections), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 486 (pneumonia, organism unspecified).

Notes that apply from higher levels

Instructions written at a parent level also apply to J18.9.

› From J18 Pneumonia, unspecified organism
Excludes1
  • congenital pneumonia (P23.0)
  • drug-induced interstitial lung disorder (J70.2-J70.4)
  • interstitial pneumonia NOS (J84.9)
  • neonatal aspiration pneumonia (P24.-)
  • pneumonitis due to fumes and vapors (J68.0)
  • usual interstitial pneumonia (J84.178)
Excludes2
  • abscess of lung with pneumonia (J85.1)
  • aspiration pneumonia due to anesthesia during labor and delivery (O74.0)
  • aspiration pneumonia due to anesthesia during pregnancy (O29)
  • aspiration pneumonia due to anesthesia during puerperium (O89.0)
  • aspiration pneumonia due to solids and liquids (J69.-)
  • aspiration pneumonia NOS (J69.0)
  • lipid pneumonia (J69.1)
  • pneumonitis due to external agents (J67-J70)
Code first
Code also
  • , if applicable, any associated condition such as:
  • aspiration pneumonia (J69.-)

Broader instructions also apply from J09-J18 Influenza and pneumonia and Chapter 10: Diseases of the respiratory system.

Alphabetic index entries

3 entries

Terms in the official ICD-10-CM index that lead to J18.9.

Codes whose notes reference J18.9

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

ICD-9-CM equivalent

Converter →
  • 486Pneumonia, organism unspecifiedapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about J18.9

Is J18.9 billable?

Yes. J18.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can J18.9 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict J18.9 as a principal diagnosis.

Is J18.9 a CC or MCC?

J18.9 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does J18.9 group to?

J18.9 is used in the MS-DRG v44.0 logic for MS-DRG 193 (Simple Pneumonia and Pleurisy with MCC), MS-DRG 194 (Simple Pneumonia and Pleurisy with CC), MS-DRG 195 (Simple Pneumonia and Pleurisy without CC/MCC), MS-DRG 791 (Prematurity with Major Problems), MS-DRG 793 (Full Term Neonate with Major Problems), MS-DRG 974 (HIV with Major Related Condition with MCC) and 2 more. Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for J18.9?

The CMS General Equivalence Mappings map J18.9 to ICD-9-CM 486.