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N61.0 ICD-10-CM Code: Mastitis without abscess

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
4 inclusion terms · 5 Excludes1

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 600 — NON-MALIGNANT BREAST DISORDERS WITH CC/MCC (MDC 09)
  • MS-DRG 601 — NON-MALIGNANT BREAST DISORDERS WITHOUT CC/MCC (MDC 09)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for N61.0 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 N61.0 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Infective mastitis (acute) (nonpuerperal) (subacute)
  • Mastitis (acute) (nonpuerperal) (subacute) NOS
  • Cellulitis (acute) (nonpuerperal) (subacute) of breast NOS
  • Cellulitis (acute) (nonpuerperal) (subacute) of nipple NOS

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).

Coder workflow for N61.0

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

Before you code N61.0

  1. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with N61.0. 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 a condition named in N61.0’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.

    ReviewC50.A, O91, P39.0

Consider N61.0. Then 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 associated condition or complication
Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

Official instructions as workflow

  • Excludes1 — check before selecting N61.0(5 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with N61.0: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareC50.A, O91, P39.0

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

Coding decision scenarios

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

Documentation: Both the condition N61.0 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).

ReviewC50.A, O91, P39.0

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

Mastitis without abscess is a billable ICD-10-CM diagnosis code (N61.0).

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

Indexed Clinical Terms (16)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

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 N61.0 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 Excludes2 note: L03.31 — Cellulitis of trunk.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 600 (MDC 09), DRG 601 (MDC 09).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):GEN017 — Nonmalignant breast conditions (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Nonmalignant breast conditions).

N60.41 — Mammary duct ectasia of right breast, N60.42 — Mammary duct ectasia of left breast, N60.49 — Mammary duct ectasia of unspecified breast, N60.81 — Other benign mammary dysplasias of right breast, N60.82 — Other benign mammary dysplasias of left breast, N60.89 — Other benign mammary dysplasias of unspecified breast, N60.91 — Unspecified benign mammary dysplasia of right breast, N60.92 — Unspecified benign mammary dysplasia of left breast, N60.99 — Unspecified benign mammary dysplasia of unspecified breast, N61 — Inflammatory disorders of breast, N61.1 — Abscess of the breast and nipple, N61.20 — Granulomatous mastitis, unspecified breast, N61.21 — Granulomatous mastitis, right breast, N61.22 — Granulomatous mastitis, left breast, N61.23 — Granulomatous mastitis, bilateral breast, N62 — Hypertrophy of breast, N63 — Unspecified lump in breast, N63.0 — Unspecified lump in unspecified breast, N63.10 — Unspecified lump in the right breast, unspecified quadrant, N63.11 — Unspecified lump in the right breast, upper outer quadrant, +65 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Fistula”, “Cellulitis”, “Inflammation, inflamed, inflammatory”, …; these codes share that main term but sit in a different category of the Tabular List.

N42.89 — Other specified disorders of prostate (prostate), N48.22 — Cellulitis of corpus cavernosum and penis (penis), N48.29 — Other inflammatory disorders of penis (penis), N48.89 — Other specified disorders of penis (penis), N49.0 — Inflammatory disorders of seminal vesicle (seminal vesicle), N49.1 — Inflammatory disorders of spermatic cord, tunica vaginalis and vas deferens (vas deferens), N49.2 — Inflammatory disorders of scrotum (scrotum), N49.8 — Inflammatory disorders of other specified male genital organs (genital organ NEC, male, specified NEC), N49.9 — Inflammatory disorder of unspecified male genital organ (genital organ NEC, male), N50.89 — Other specified disorders of the male genital organs (scrotum), N64.0 — Fissure and fistula of nipple (nipple), N73.0 — Acute parametritis and pelvic cellulitis (periuterine, acute), N73.2 — Unspecified parametritis and pelvic cellulitis (periuterine), N75.8 — Other diseases of Bartholin's gland (Bartholin's gland), N76.4 — Abscess of vulva (genital organ NEC, female), N82.0 — Vesicovaginal fistula (vesicovaginal), N82.1 — Other female urinary-genital tract fistulae (uterovesical), N82.2 — Fistula of vagina to small intestine (ileovaginal), N82.3 — Fistula of vagina to large intestine (rectovaginal), N82.4 — Other female intestinal-genital tract fistulae (vulvorectal), +245 more

Contextual Map

Every relationship of N61.0 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 N61.0 with this related code in Claim Check

Hierarchy

Referenced by Excludes2 notes

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 09 — Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast[MDC crossing]: “Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 7,376 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries (16)

  • Cellulitis (diffuse) (phlegmonous) (septic) (suppurative), breast (acute) (nonpuerperal) (subacute)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Cellulitis (diffuse) (phlegmonous) (septic) (suppurative), breast (acute) (nonpuerperal) (subacute), nipple[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Cellulitis (diffuse) (phlegmonous) (septic) (suppurative), nipple (acute) (nonpuerperal) (subacute)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Fistula (cutaneous), breast[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Fistula (cutaneous), mammary (gland)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Galactophoritis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Infection, infected, infective (opportunistic), mammary gland[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Infection, infected, infective (opportunistic), nipple[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 8 more

Nearest codes

Change history

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
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 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. "N61.0 — Mastitis without abscess." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/n61.0-mastitis-without-abscess

Change history

  • FY2017 — October 1, 2016
    Added to the code set
    Mastitis without abscess
    FY2017 changes

Nearest Codes in This Family

Official ICD-10-CM classifications closest to N61.0 in its code family, with their registry titles.

View all codes in the N61 family