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J18 ICD-10-CM Code: Pneumonia, unspecified organism

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Coding at a Glance

Tabular directives
6 Excludes1 · 14 Excludes2 · 1 use-additional code · 1 code-first instruction · 2 code-also instructions

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for J18 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on J18 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Code First

Underlying conditions that must be sequenced before this code.

Code Also

Additional codes that may be required to fully describe the encounter.

  • Code also, if applicable, any associated condition such as:
  • aspiration pneumonia (J69.-)

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code, if applicable, to identify resistance to antimicrobial drugs (Z16.-)

Source: inherited from J09-J18

Coder workflow for J18

MedCoder structured workflow — derived from this code’s own official record

Before you code J18

  1. J18 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewJ18.0, J18.1, J18.2, J18.8, J18.9

    See the relationships section · Guide: How to choose an ICD-10-CM code →

  2. Unspecified does not mean incorrect. When the record gives no greater specificity, J18 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with J18. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support one of the more specific codes beneath J18?
    Yes → Select that code and continue the checks below on its own page.
    No → J18 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewJ18.0, J18.1, J18.2, J18.8, J18.9

  2. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — J18 is appropriate when the documentation goes no further.
  3. Does the documentation support a condition named in J18’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewP23.0, J84.9, P24, J68.0, J84.178

  4. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then J18.
    No → Continue; do not add an underlying condition the record does not document.

    ReviewJ09.X1, J10.0, J11.0

Consider J18. Then work the Use Additional Code note and review the Code Also note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes1 — check before selecting J18(6 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with J18: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareP23.0, J84.9, P24, J68.0, J84.178

    See the official tabular notes · Guidelines I.A.12.a

  • Excludes2 — not part of J18(14 notes)

    Coding workflow: The conditions named in this note are not included in J18. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareJ85.1, O74.0, O29, O89.0, J69, J69.0

    See the official tabular notes · Guidelines I.A.12.b

  • Code First — sequencing check(1 note)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before J18. Do not add an underlying condition the record does not document.

    ReviewJ09.X1, J10.0, J11.0

    See the official tabular notes · Guidelines I.A.13

  • Use Additional Code — after identifying J18(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with J18 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewZ16

    See the official tabular notes · Guidelines I.A.13

  • Code Also — related condition(2 notes)

    Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

    ReviewJ69

    See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the subcategory for a sibling that names the missing detail.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

Documentation: Both the condition J18 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewP23.0, J84.9, P24, J68.0, J84.178

Documentation: The underlying condition the Code First note names is documented alongside this condition.

Coding question: How are the two sequenced?

Path: Review the Code First note.

Reason: The underlying condition is sequenced first and the manifestation follows (Guidelines I.A.13).

ReviewJ09.X1, J10.0, J11.0

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Pneumonia, unspecified organism is a non-billable ICD-10-CM category code (J18). A more specific billable subcode must be selected for claims submission.

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 10: Diseases of the Respiratory System (J00-J99), U07.0 a. Chronic Obstructive Pulmonary Disease [COPD] and Asthma 1) Acute exacerbation of chronic obstructive bronchitis and asthma

Code J95.851, Ventilator associated pneumonia, should be assigned only when the provider has documented ventilator associated pneumonia (VAP). An additional code to identify the organism (e.g., Pseudomonas aeruginosa, code B96.5) should also be assigned. Do not assign an additional code from categories J12-J18 to identify the type of pneumonia.

Chapter 10: Diseases of the Respiratory System (J00-J99), U07.0 a. Chronic Obstructive Pulmonary Disease [COPD] and Asthma 1) Acute exacerbation of chronic obstructive bronchitis and asthma

2) Ventilator associated Pneumonia Develops after Admission A patient may be admitted with one type of pneumonia (e.g., code J13, Pneumonia due to Streptococcus pneumonia) and subsequently develop VAP. In this instance, the principal diagnosis would be the appropriate code from categories J12-J18 for the pneumonia diagnosed at the time of admission. Code J95.851, Ventilator associated pneumonia, would be assigned as an additional diagnosis when the provider has also documented the presence of ventilator associated pneumonia.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. Sequencing: 1 Code First instruction — the underlying condition is sequenced before this code when present. See the Code First notes
  2. 1 Use Additional Code instruction — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  3. 2 Code Also notes — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  4. 6 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  5. 14 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name J18 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Use Additional Code instruction: J95.89 — Other postprocedural complications and disorders of respiratory system, not elsewhere classified.

These codes instruct coders to additionally report this code when it applies.

Referenced by 1 Code Also instruction: D81.82 — Activated Phosphoinositide 3-kinase Delta Syndrome [APDS].

These codes suggest coding this condition alongside when both are present.

Contextual Map

Every relationship of J18 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run J18 with these 22 related codes in Claim Check

Hierarchy

Excludes1

Excludes2 (15)

Code First

Use Additional Code

  • Z16 — Resistance to antimicrobial drugs[Use Additional Code]: “code, if applicable, to identify resistance to antimicrobial drugs (Z16.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Code Also

Referenced by Use Additional Code instructions

Referenced by Code Also instructions

Nearest codes

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Can J18 be billed directly?

No. J18 (Pneumonia, unspecified organism) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "J18 — Pneumonia, unspecified organism." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/j18-pneumonia-unspecified-organism

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Pneumonia, unspecified organism

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to J18 in its code family, with their registry titles.