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B10.09 ICD-10-CM Code: Other human herpesvirus encephalitis

Compare with another code for B10.09Check this code on a claim

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

Coding at a Glance

Official instructions
1 inclusion term · 16 Excludes2

What these terms mean →

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too, and is marked with where it comes from.

Excludes2Not included here; may be reported together
  • herpes encephalitis NOS (B00.4) (from B10.0)
  • herpes simplex encephalitis (B00.4) (from B10.0)
  • human herpesvirus encephalitis (B00.4) (from B10.0)
  • simian B herpes virus encephalitis (B00.4) (from B10.0)

+12 more in Instructions

IncludesWhat this code covers
  • Human herpesvirus 7 encephalitis

Where it sits Source: CMS/NCHS

Under:Chapter 1: Certain Infectious and Parasitic DiseasesB10 Other human herpesvirusesB10.0 Other human herpesvirus encephalitis

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

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 v44, Appendix B.

  • MS-DRG 023 — CRANIOTOMY WITH MAJOR DEVICE IMPLANT OR ACUTE COMPLEX CNS PRINCIPAL DIAGNOSIS WITH MCC OR ANTINEOPLASTIC IMPLANT OR EPILEPSY WITH NEUROSTIMULATOR (MDC 01)
  • MS-DRG 024 — CRANIOTOMY WITH MAJOR DEVICE IMPLANT OR ACUTE COMPLEX CNS PRINCIPAL DIAGNOSIS WITHOUT MCC (MDC 01)
  • MS-DRG 097 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH MCC (MDC 01)
  • MS-DRG 098 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH CC (MDC 01)
  • MS-DRG 099 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITHOUT CC/MCC (MDC 01)
  • MS-DRG 791 — PREMATURITY WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 974 — HIV WITH MAJOR RELATED CONDITION WITH MCC (MDC 25)
  • MS-DRG 975 — HIV WITH MAJOR RELATED CONDITION WITH CC (MDC 25)
  • MS-DRG 976 — HIV WITH MAJOR RELATED CONDITION WITHOUT CC/MCC (MDC 25)

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 B10.09 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on B10.09 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Human herpesvirus 7 encephalitis

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Coder workflow for B10.09

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

Before you code B10.09

  1. “Other” (NEC) means the condition is specified in the record but no dedicated code captures it. Confirm the documented form is not one a sibling code names before settling on B10.09; if the record states no specifics at all, the unspecified sibling applies instead. “Other” codes are for documented conditions the classification gives no specific code; “unspecified” codes are for records lacking the detail (Guidelines I.A.9.a, I.A.9.b).

    ReviewB10.01

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

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 code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes2 — not part of B10.09(16 notes)

    Coding workflow: The conditions named in this note are not included in B10.09. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareB00.4, B25.9, B27.0, B00.9, B00, B02

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

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.

Don’t confuse B10.09 with…

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

The codes most likely to be picked instead of B10.09 — 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.

  • B00.4— 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 herpes encephalitis NOS adds B00.4; it is not part of this code and both may be reported when both are documented.

    Full comparison: B10.09 vs B00.4 →

  • B25.9— 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 cytomegalovirus adds B25.9; it is not part of this code and both may be reported when both are documented.

    Full comparison: B10.09 vs B25.9 →

  • B27.0— 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 Epstein-Barr virus adds B27.0; it is not part of this code and both may be reported when both are documented.

    Full comparison: B10.09 vs B27.0 →

  • B00.9— 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 herpes NOS adds B00.9; it is not part of this code and both may be reported when both are documented.

    Full comparison: B10.09 vs B00.9 →

  • B00— 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 herpes encephalitis NOS adds B00; it is not part of this code and both may be reported when both are documented.

    Full comparison: B10.09 vs B00 →

  • B02— 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 herpes zoster adds B02; it is not part of this code and both may be reported when both are documented.

    Full comparison: B10.09 vs B02 →

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.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Other human herpesvirus encephalitis is a billable ICD-10-CM diagnosis code (B10.09).

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

Verify Before Coding

  • MCC as a secondary diagnosis (FY2027). 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-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name B10.09 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 3 Excludes1 notes: A85 — Other viral encephalitis, not elsewhere classified (via B10.0.-), B00.4 — Herpesviral encephalitis (via B10.0.-), B00.4 — Herpesviral encephalitis.

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 B10.-).

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 (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: MCC — Major 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 13 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 10 MS-DRGs: DRG 023 (MDC 01), DRG 024 (MDC 01), DRG 097 (MDC 01), DRG 098 (MDC 01), DRG 099 (MDC 01), DRG 791 (MDC 15), DRG 793 (MDC 15), 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):NVS002 — Encephalitis (default); INF008 — Viral infection.

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 MCC — 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.

B00.4 — Herpesviral encephalitis, B00.82 — Herpes simplex myelitis, B00.89 — Other herpesviral infection, B00.9 — Herpesviral infection, unspecified, B10.01 — Human herpesvirus 6 encephalitis, B10.81 — Human herpesvirus 6 infection, B10.82 — Human herpesvirus 7 infection, B10.89 — Other human herpesvirus infection, B92 — Sequelae of leprosy, B94.2 — Sequelae of viral hepatitis, B94.8 — Sequelae of other specified infectious and parasitic diseases, B94.9 — Sequelae of unspecified infectious and parasitic disease

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Encephalitis, Viral infection).

A85.8 — Other specified viral encephalitis, A86 — Unspecified viral encephalitis, A92.2 — Venezuelan equine fever, A92.31 — West Nile virus infection with encephalitis, B00.4 — Herpesviral encephalitis, B01.11 — Varicella encephalitis and encephalomyelitis, B02.0 — Zoster encephalitis, B05.0 — Measles complicated by encephalitis, B06.01 — Rubella encephalitis, B10.01 — Human herpesvirus 6 encephalitis, B26.2 — Mumps encephalitis, B40.81 — Blastomycotic meningoencephalitis, B57.42 — Meningoencephalitis in Chagas' disease, B58.2 — Toxoplasma meningoencephalitis, B60.11 — Meningoencephalitis due to Acanthamoeba (culbertsoni), G04.00 — Acute disseminated encephalitis and encephalomyelitis, unspecified, G04.01 — Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM), G04.02 — Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis, G04.2 — Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified, G04.30 — Acute necrotizing hemorrhagic encephalopathy, unspecified, +314 more

Same Index main term, other category

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

B02.31 — Zoster conjunctivitis (conjunctivitis, zoster), B02.32 — Zoster iridocyclitis (iridocyclitis, zoster), B02.33 — Zoster keratitis (cornea), B02.39 — Other herpes zoster eye disease (eyelid), B02.7 — Disseminated zoster (zoster, disseminated), B02.8 — Zoster with other complications (zoster, complicated NEC), B02.9 — Zoster without complications (zoster), B05.0 — Measles complicated by encephalitis (in, measles), B06.01 — Rubella encephalitis (in, rubella), B09 — Unspecified viral infection characterized by skin and mucous membrane lesions (postexanthematous NEC), B20 — Human immunodeficiency virus [HIV] disease (due to, human immunodeficiency virusdisease), B25.8 — Other cytomegaloviral diseases (in, cytomegalovirus), B26.2 — Mumps encephalitis (in, mumps), B35.0 — Tinea barbae and tinea capitis (tonsurans), B35.4 — Tinea corporis (circinatus), B40.81 — Blastomycotic meningoencephalitis (in, blastomycosis NEC), B45.1 — Cerebral cryptococcosis (Torula, torular), B56.9 — African trypanosomiasis, unspecified (in, African trypanosomiasis), B57.42 — Meningoencephalitis in Chagas' disease (in, Chagas' disease), B58.2 — Toxoplasma meningoencephalitis (in, toxoplasmosis), +89 more

Contextual Map

Every relationship of B10.09 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 B10.09 with these 3 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Code First instructions

Clinical classification (CCSR)

MS-DRG Grouper (10)

MDC crossing

  • MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — 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. 8,919 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027
  • MDC 15 — Newborns and Other Neonates with Conditions Originating in Perinatal Period[MDC crossing]: “Newborns and Other Neonates with Conditions Originating in Perinatal Period — 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 · FY2027

Index entries (11)

  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), herpesviral, due to herpesvirus 7[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), herpesviral, specified NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), in (due to), herpesvirus (simplex), due to herpesvirus 7[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), in (due to), herpesvirus (simplex), specified NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Herpes, herpesvirus, herpetic, encephalitis, due to herpesvirus 7[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Herpes, herpesvirus, herpetic, encephalitis, specified NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Herpes, herpesvirus, herpetic, human, 7, encephalitis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Meningoencephalitis, herpesviral, herpetic, due to herpesvirus 7[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • and 3 more

Nearest codes

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Indexed Clinical Terms (11)

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.

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 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 — v44 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-derived 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 editorial 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.

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

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

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. "B10.09 — Other human herpesvirus encephalitis." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/b10.09-other-human-herpesvirus-encephalitis

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Other human herpesvirus encephalitis

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, 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 B10.09 in its code family, with their registry titles.

View all codes in the B10 family