B47.9 ICD-10-CM Code: Mycetoma, unspecified

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for B47.9 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 B47.9 itself; “inherited from” names the category or block whose note applies here.

This page already reflects the FY2027 tabular note taking effect October 1, 2026.

Coder workflow for B47.9

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

Before you code B47.9

1. Unspecified does not mean incorrect. When the record gives no greater specificity, B47.9 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).

   ReviewB47.0, B47.1

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

Choose the right path

1. Does the record document the detail a more specific sibling code needs?
   Yes → Review the specific siblings in this subcategory.
   No → Continue — B47.9 is appropriate when the documentation goes no further.

   ReviewB47.0, B47.1

Consider B47.9. 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).

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

• Excludes2 — not part of B47.9(3 notes)

  Coding workflow: The conditions named in this note are not included in B47.9. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareJ4B, J67, C84.0

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

Coding decision scenarios

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

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.

Indexed Clinical Terms (6)

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.

• Infection, infected, infective (opportunistic), mycetoma
• Madura, foot
• Mycetoma
• Mycetoma, bone (mycotic)
• Mycetoma, foot
• Mycetoma, madurae NEC

Don’t confuse B47.9 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of B47.9 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• J4B— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of pulmonary mycetoma adds J4B; it is not part of this code and both may be reported when both are documented.

  Full comparison: B47.9 vs J4B →

• J67— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypersensitivity pneumonitis due to organic dust adds J67; it is not part of this code and both may be reported when both are documented.

  Full comparison: B47.9 vs J67 →

• C84.0— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of mycosis fungoides adds C84.0; it is not part of this code and both may be reported when both are documented.

  Full comparison: B47.9 vs C84.0 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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 B47.9 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 Code First instruction: M01 — Direct infections of joint in infectious and parasitic diseases classified elsewhere (via B47.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 8 clinically related codes on its CMS exclusion list. Does not count toward severity when the stay groups to DRGs 974-976 (HIV with Major Related Condition).

Named in the grouper logic of 5 MS-DRGs: DRG 606 (MDC 09), DRG 607 (MDC 09), DRG 974 (MDC 25), DRG 975 (MDC 25), DRG 976 (MDC 25).

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

Clinical classification (AHRQ CCSR):INF004 — Fungal infections (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 process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

A42.81 — Actinomycotic meningitis, A42.82 — Actinomycotic encephalitis, A42.89 — Other forms of actinomycosis, A42.9 — Actinomycosis, unspecified, A43.8 — Other forms of nocardiosis, A43.9 — Nocardiosis, unspecified, B47.1 — Actinomycetoma

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Fungal infections).

B45.9 — Cryptococcosis, unspecified, B46.0 — Pulmonary mucormycosis, B46.1 — Rhinocerebral mucormycosis, B46.2 — Gastrointestinal mucormycosis, B46.3 — Cutaneous mucormycosis, B46.4 — Disseminated mucormycosis, B46.5 — Mucormycosis, unspecified, B46.8 — Other zygomycoses, B46.9 — Zygomycosis, unspecified, B47.0 — Eumycetoma, B47.1 — Actinomycetoma, B48.0 — Lobomycosis, B48.1 — Rhinosporidiosis, B48.2 — Allescheriasis, B48.3 — Geotrichosis, B48.4 — Penicillosis, B48.8 — Other specified mycoses, B49 — Unspecified mycosis, B59 — Pneumocystosis, P37.5 — Neonatal candidiasis, +86 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Mycetoma”; these codes share that main term but sit in a different category of the Tabular List.

J4B — Pulmonary mycetoma

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

HIV Screening Test

Contextual Map

Every relationship of B47.9 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 B47.9 with this related code in Claim Check

Hierarchy

• A00-B99 — Chapter 1: Certain Infectious and Parasitic Diseases (A00-B99) (A00-B99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B35-B49 — Mycoses[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Index manifestation

• M90.80 — Osteopathy in diseases classified elsewhere, unspecified site[Index manifestation]: “Mycetoma, bone”— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Referenced by Code First instructions

• M01 — Direct infections of joint in infectious and parasitic diseases classified elsewhere[Code First](via B47.-): “mycoses (B35-B49)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• INF004 — Fungal infections[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC). Not counted when the stay groups to DRGs 974-976 (HIV with Major Related Condition).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 606 — MINOR SKIN DISORDERS WITH MCC[MS-DRG]: “MINOR SKIN DISORDERS WITH MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 607 — MINOR SKIN DISORDERS WITHOUT MCC[MS-DRG]: “MINOR SKIN DISORDERS WITHOUT MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 974 — HIV WITH MAJOR RELATED CONDITION WITH MCC[MS-DRG]: “HIV WITH MAJOR RELATED CONDITION WITH MCC (MDC 25)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 975 — HIV WITH MAJOR RELATED CONDITION WITH CC[MS-DRG]: “HIV WITH MAJOR RELATED CONDITION WITH CC (MDC 25)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 976 — HIV WITH MAJOR RELATED CONDITION WITHOUT CC/MCC[MS-DRG]: “HIV WITH MAJOR RELATED CONDITION WITHOUT CC/MCC (MDC 25)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

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
• MDC 25 — Human Immunodeficiency Virus Infections[MDC crossing]: “Human Immunodeficiency Virus Infections — 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.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Infection, infected, infective (opportunistic), mycetoma[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Madura, foot[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Mycetoma[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Mycetoma, bone (mycotic)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Mycetoma, foot[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Mycetoma, madurae NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• B47 — Mycetoma[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B47.0 — Eumycetoma[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• B47.1 — Actinomycetoma[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history (2)

• FY2027 — Excludes2 note will be added[Change history]— CMS release files (code change ledger) · icd10cm-fy2027
• and 1 more

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to B47.9 in its code family, with their registry titles.

• B47 — Mycetoma
• B47.0 — Eumycetoma
• B47.1 — Actinomycetoma

View all codes in the B47 family