B33.8 ICD-10-CM Code: Other specified viral diseases
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Coding at a Glance
- Tabular directives
- 2 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 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 B33.8 in the official ICD-10-CM tabular list, quoted as published.
Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025
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).
- anogenital human papillomavirus infection (A63.0) Compare B33.8 vs A63.0 →
- viral warts due to human papillomavirus infection (B07) Compare B33.8 vs B07 →
Coder workflow for B33.8
MedCoder structured workflow — derived from this code’s own official record
Before you code B33.8
- “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 B33.8; 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).
ReviewB33.0, B33.1, B33.2, B33.4
See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →
- Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with B33.8. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).
Choose the right path
- Does the documentation support a condition named in B33.8’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.
Consider B33.8. 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
Excludes1 — check before selecting B33.8(2 notes)
Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with B33.8: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.
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 B33.8 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).
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
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 (8)
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.
- Aujeszky's disease
- Coxsackie (virus) (infection), specific disease NEC
- Disease, diseased, viral, virus, Tahyna
- Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), Tahyna
- Hepatitis, viral, virus, coxsackie
- Infection, infected, infective (opportunistic), virus, viral NOS, specified type NEC
- Lymphocytosis (symptomatic), infectious (acute)
- Tahyna fever
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 B33.8 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: H67 — Otitis media in diseases classified elsewhere (via B33.-).
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).
Same Index main term, other category
The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Coxsackie”, “Fever”, “Hepatitis”, …; these codes share that main term but sit in a different category of the Tabular List.
B18.9 — Chronic viral hepatitis, unspecified (viral, virus, chronic), B19.0 — Unspecified viral hepatitis with hepatic coma (viral, virus, with hepatic coma), B19.10 — Unspecified viral hepatitis B without hepatic coma (B), B19.11 — Unspecified viral hepatitis B with hepatic coma (B, with), B19.20 — Unspecified viral hepatitis C without hepatic coma (C), B19.21 — Unspecified viral hepatitis C with hepatic coma (C, with hepatic coma), B19.9 — Unspecified viral hepatitis without hepatic coma (viral, virus), B25.1 — Cytomegaloviral hepatitis (cytomegaloviral), B26.81 — Mumps hepatitis (in, mumps), B30.2 — Viral pharyngoconjunctivitis (pharyngoconjunctival), B34.1 — Enterovirus infection, unspecified, B38.0 — Acute pulmonary coccidioidomycosis (desert), B50.8 — Other severe and complicated Plasmodium falciparum malaria (blackwater), B50.9 — Plasmodium falciparum malaria, unspecified (Panama), B52.9 — Plasmodium malariae malaria without complication (quartan), B53.0 — Plasmodium ovale malaria (Plasmodium ovale), B55.0 — Visceral leishmaniasis (Assam), B58.1 — Toxoplasma hepatitis (in, toxoplasmosis), B65.2 — Schistosomiasis due to Schistosoma japonicum (Katayama), B83.9 — Helminthiasis, unspecified (worm), +170 more
Contextual Map
Every relationship of B33.8 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 B33.8 with these 3 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
Excludes1
- A63.0 — Anogenital (venereal) warts[Excludes1]: “anogenital human papillomavirus infection (A63.0)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
- B07 — Viral warts[Excludes1]: “viral warts due to human papillomavirus infection (B07)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
Index manifestation
- K77 — Liver disorders in diseases classified elsewhere[Index manifestation]: “Hepatitis, viral, virus, coxsackie”— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
Referenced by Code First instructions
- H67 — Otitis media in diseases classified elsewhere[Code First](via B33.-): “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
- Aujeszky's disease[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
- Coxsackie (virus) (infection), specific disease NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
- Disease, diseased, viral, virus, Tahyna[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
- Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), Tahyna[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
- Hepatitis, viral, virus, coxsackie[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
- Infection, infected, infective (opportunistic), virus, viral NOS, specified type NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
- Lymphocytosis (symptomatic), infectious (acute)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
- Tahyna fever[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
Nearest codes (11)
- B33 — Other viral diseases, not elsewhere classified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B33.0 — Epidemic myalgia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B33.1 — Ross River disease[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B33.2 — Viral carditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B33.20 — Viral carditis, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B33.21 — Viral endocarditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B33.22 — Viral myocarditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- B33.23 — Viral pericarditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
- and 3 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. "B33.8 — Other specified viral diseases." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/b33.8-other-specified-viral-diseases
Change history
- FY2016 — October 1, 2015In the code set at ICD-10-CM adoptionOther specified viral diseases
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 B33.8 in its code family, with their registry titles.
- B33.0 — Epidemic myalgia
- B33.1 — Ross River disease
- B33.2 — Viral carditis
- B33.20 — Viral carditis, unspecified
- B33.21 — Viral endocarditis
- B33.22 — Viral myocarditis
- B33.23 — Viral pericarditis
- B33.24 — Viral cardiomyopathy
- B33.3 — Retrovirus infections, not elsewhere classified
- B33.4 — Hantavirus (cardio)-pulmonary syndrome [HPS] [HCPS]