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L04 vs R59.1

L04 (Acute lymphadenitis) compared with R59.1 (Generalized enlarged lymph nodes), 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 should not be reported together because L04’s tabular entry lists R59.1 under Excludes1.

Official rule
What is different?

The conditions named, billing status and chapter.L04 is “Acute lymphadenitis”; R59.1 is “Generalized enlarged lymph nodes”. L04 is a non-billable header; R59.1 is billable. L04 sits in L00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99); R59.1 in R00-R99 — Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99).

Registry fact

Can these codes be reported together?

No.L04’s entry carries an Excludes1 note covering R59.1: “enlarged lymph nodes (R59.-)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.L04’s tabular entry: “enlarged lymph nodes (R59.-)”. The note covers R59.1.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code. L04 carries 13 Excludes2 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.

Is one a parent or header code?

One is a header.L04 is a non-billable header, but R59.1 is not one of its subdivisions.

Registry fact

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?

Excludes1 — generally not reported together

Excludes1 conflict

L04
Acute lymphadenitis
↔
R59.1
Generalized enlarged lymph nodes

What we found

No — do not report together.L04 carries an Excludes1 note covering R59.1: “enlarged lymph nodes (R59.-)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes1 note means the two conditions are not ordinarily reported together for the same encounter, because the classification treats them as mutually exclusive forms of the same condition. The documented exception is when the two conditions are unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Official guidance behind these answers

  • Section I.A.12.a — Excludes1 · applies to: Excludes1

    A type 1 Excludes note is a pure excludes note. It means “NOT CODED HERE!” An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," because "teeth grinding" is an inclusion term under F45.8. Only one of these two codes should be assigned for teeth grinding. However psychogenic dysmenorrhea is also an inclusion term under F45.8, and a patient could have both this condition and sleep related teeth grinding. In this case, the two conditions are clearly unrelated to each other, and so it would be appropriate to report F45.8 and G47.63 together.

    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
L04

Acute lymphadenitis

R59.1

Generalized enlarged lymph nodes

StatusDiffers
L04
Non-billable header

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

Report instead: L04.0, L04.1, L04.2, L04.3, L04.8

R59.1
Billable
Excludes1Differs
L04
  • chronic or subacute lymphadenitis, except mesenteric (I88.1)
  • enlarged lymph nodes (R59.-)
  • human immunodeficiency virus [HIV] disease resulting in generalized lymphadenopathy (B20)
  • lymphadenitis NOS (I88.9)
  • nonspecific mesenteric lymphadenitis (I88.0)
R59.1
  • lymphadenitis NOS (I88.9)
  • acute lymphadenitis (L04.-)
  • chronic lymphadenitis (I88.1)
  • mesenteric (acute) (chronic) lymphadenitis (I88.0)
Excludes2Differs
L04
  • hordeolum (H00.0)
  • infective dermatitis (L30.3)
  • local infections of skin classified in Chapter 1
  • lupus panniculitis (L93.2)
  • panniculitis NOS (M79.3)
  • panniculitis of neck and back (M54.0-)
  • Perlèche NOS (K13.0)
  • Perlèche due to candidiasis (B37.0)
  • Perlèche due to riboflavin deficiency (E53.0)
  • pyogenic granuloma (L98.0)
  • relapsing panniculitis [Weber-Christian] (M35.6)
  • viral warts (B07.-)
  • zoster (B02.-)
R59.1

None at this code

Use additional codeDiffers
L04
  • code (B95-B97) to identify infectious agent.
R59.1

None at this code

CategoryDiffers
L04

Is itself a category

R59.1

R59 Enlarged lymph nodes

ChapterDiffers
L04

L00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99)

R59.1

R00-R99 — Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99)

IncludesDiffers
L04
  • abscess (acute) of lymph nodes, except mesenteric
  • acute lymphadenitis, except mesenteric
R59.1
  • swollen glands
  • Lymphadenopathy NOS

No Code first, Code also and 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, notes every code shares are dimmed.

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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