B26.9 ICD-10-CM Code: Mumps without complication
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Coding at a Glance
- Tabular directives
- 4 inclusion terms
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 865 — VIRAL ILLNESS WITH MCC (MDC 18)
- MS-DRG 866 — VIRAL ILLNESS WITHOUT MCC (MDC 18)
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 B26.9 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 B26.9 itself; “inherited from” names the category or block whose note applies here.
Includes
Conditions the official ICD-10-CM tabular list includes under this code.
- epidemic parotitis
- infectious parotitis
Source: inherited from B26
Inclusion Terms
Alternative terms the tabular list files under this code.
- Mumps NOS
- Mumps parotitis NOS
Code Overview
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 (1)
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 B26.9 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 Excludes1 note: K11.2 — Sialoadenitis (via B26.-).
These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.
Referenced by 1 Code First instruction: H67 — Otitis media in diseases classified elsewhere (via B26.-).
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: 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 865 (MDC 18), DRG 866 (MDC 18).
From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.
Clinical classification (AHRQ CCSR):INF008 — Viral infection (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 (Viral infection).
Contextual Map
Every relationship of B26.9 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 B26.9 with these 2 related codes 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
- B25-B34 — Other viral diseases[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
Referenced by Excludes1 notes
- K11.2 — Sialoadenitis[Excludes1](via B26.-): “epidemic parotitis (B26.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
Referenced by Code First instructions
- H67 — Otitis media in diseases classified elsewhere[Code First](via B26.-): “viral disease NEC (B00-B34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
Clinical classification (CCSR)
- INF008 — Viral infection[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
MS-DRG Grouper
- DRG 865 — VIRAL ILLNESS WITH MCC[MS-DRG]: “VIRAL ILLNESS WITH MCC (MDC 18)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
- DRG 866 — VIRAL ILLNESS WITHOUT MCC[MS-DRG]: “VIRAL ILLNESS WITHOUT MCC (MDC 18)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
MDC crossing
- MDC 18 — Infectious and Parasitic Diseases, Systemic or Unspecified Sites[MDC crossing]: “Infectious and Parasitic Diseases, Systemic or Unspecified Sites — 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. 1 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026
Index entries
- Mumps[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
Nearest codes (12)
- B26 — Mumps[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B26.0 — Mumps orchitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B26.1 — Mumps meningitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B26.2 — Mumps encephalitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B26.3 — Mumps pancreatitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B26.8 — Mumps with other complications[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B26.81 — Mumps hepatitis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B26.82 — Mumps myocarditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- and 4 more
Change history
- FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016
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. "B26.9 — Mumps without complication." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/b26.9-mumps-without-complication
Change history
- FY2016 — October 1, 2015In the code set at ICD-10-CM adoptionMumps without complication
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 B26.9 in its code family, with their registry titles.