Skip to main content

J18.1 vs O29

J18.1 (Lobar pneumonia, unspecified organism) compared with O29 (Complications of anesthesia during pregnancy), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because J18.1 lists O29 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named, billing status and chapter.J18.1 is “Lobar pneumonia, unspecified organism”; O29 is “Complications of anesthesia during pregnancy”. O29 is a non-billable header; J18.1 is billable. J18.1 sits in J00-J99 — Diseases of the Respiratory System (J00-J99); O29 in O00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A).

Registry fact

Can these codes be reported together?

Yes, when both are documented.J18.1 lists O29 under Excludes2: “aspiration pneumonia due to anesthesia during pregnancy (O29)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.J18.1’s tabular entry: “aspiration pneumonia due to anesthesia during pregnancy (O29)”. The note covers O29.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

One is a header.O29 is a non-billable header, but J18.1 is not one of its subdivisions.

Registry fact

Nothing found in 3 other checks; 1 check does not apply
Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. J18.1 carries 6 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

J18.1
Lobar pneumonia, unspecified organism
↔
O29
Complications of anesthesia during pregnancy

What we found

Yes, when both are documented.J18.1 carries an Excludes2 note covering O29: “aspiration pneumonia due to anesthesia during pregnancy (O29)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
J18.1

Lobar pneumonia, unspecified organism

O29

Complications of anesthesia during pregnancy

StatusDiffers
J18.1
Billable
O29
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: O29.011, O29.012, O29.013, O29.019, O29.021

Excludes1Differs
J18.1
  • 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)
O29

None at this code

Excludes2Differs
J18.1
  • 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)
  • allergic or eosinophilic pneumonia (J82)
  • meconium pneumonia (P24.01)
  • pneumonia due to solids and liquids (J69.-)
  • congenital pneumonia (P23.9)
  • rheumatic pneumonia (I00)
  • ventilator associated pneumonia (J95.851)
O29
  • complications of anesthesia during labor and delivery (O74.-)
  • complications of anesthesia during the puerperium (O89.-)
  • maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48)
  • maternal diseases classifiable elsewhere but complicating pregnancy, labor and delivery, and the puerperium (O98-O99)
Code firstDiffers
J18.1
  • , if applicable, associated influenza (J09.X1, J10.0-, J11.0-)
O29

None at this code

Use additional codeDiffers
J18.1
  • code, if applicable, to identify resistance to antimicrobial drugs (Z16.-)
O29
  • code, if necessary, to identify the complication
Code alsoDiffers
J18.1
  • , if applicable, any associated condition such as:
  • aspiration pneumonia (J69.-)
O29

None at this code

CategoryDiffers
J18.1

J18 Pneumonia, unspecified organism

O29

Is itself a category

ChapterDiffers
J18.1

J00-J99 — Diseases of the Respiratory System (J00-J99)

O29

O00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A)

IncludesDiffers
J18.1

None at this code

O29
  • maternal complications arising from the administration of a general, regional or local anesthetic, analgesic or other sedation during pregnancy

No 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

Edit this comparisonCheck a whole claim

Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources