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B18.9 ICD-10-CM Code: Chronic viral hepatitis, unspecified

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

Coding at a Glance

Tabular directives
2 inclusion terms · 1 Excludes1 · 2 Excludes2 · 1 use-additional code
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 29

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 441 — DISORDERS OF LIVER EXCEPT MALIGNANCY, CIRRHOSIS OR ALCOHOLIC HEPATITIS WITH MCC (MDC 07)
  • MS-DRG 442 — DISORDERS OF LIVER EXCEPT MALIGNANCY, CIRRHOSIS OR ALCOHOLIC HEPATITIS WITH CC (MDC 07)
  • MS-DRG 443 — DISORDERS OF LIVER EXCEPT MALIGNANCY, CIRRHOSIS OR ALCOHOLIC HEPATITIS WITHOUT CC/MCC (MDC 07)
  • MS-DRG 791 — PREMATURITY WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)

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.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 65 — Chronic Hepatitis

Other models: CMS-HCC V22 HCC 29

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for B18.9 in the official ICD-10-CM tabular list, quoted as published.

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

Notes without a marker are published on B18.9 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.

  • Carrier of viral hepatitis

Source: inherited from B18

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Carrier of unspecified viral hepatitis

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).

Source: inherited from B15-B19

Excludes2 — Not Included Here

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

Source: inherited from B15-B19

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code, if applicable, for ascites (R18.8)

Source: inherited from B18

Coder workflow for B18.9

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

Before you code B18.9

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, B18.9 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by acute versus chronic, the presence or absence of the associated condition. 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).

    ReviewB18.0, B18.1, B18.2, B18.8

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

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with B18.9. 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 record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — B18.9 is appropriate when the documentation goes no further.

    ReviewB18.0, B18.1, B18.2, B18.8

  2. Does the documentation support a condition named in B18.9’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.

    ReviewB94.2

Consider B18.9. Then work the Use Additional Code note, and 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).
Acuity
Acute or chronic as documented; when both are documented and separate codes exist, both are reported with the acute code first (Guidelines I.B.8).
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).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
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 B18.9(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with B18.9: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareB94.2

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

  • Excludes2 — not part of B18.9(2 notes)

    Coding workflow: The conditions named in this note are not included in B18.9. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareB25.1, B00.81

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

  • Use Additional Code — after identifying B18.9(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with B18.9 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewR18.8

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

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

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewB18.0, B18.1, B18.2, B18.8

Documentation: Both the condition B18.9 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).

ReviewB94.2

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with B18.9?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewR18.8

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

Chronic viral hepatitis, unspecified is a billable ICD-10-CM diagnosis code (B18.9).

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 (3)

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.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. 1 Use Additional Code instruction — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 1 Excludes1 entry — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  3. 2 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • CC 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 structured relationships — computed from published CMS and AHRQ datasets

Other codes that name B18.9 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 4 Excludes1 notes: K73 — Chronic hepatitis, not elsewhere classified (via B18.-), K75.2 — Nonspecific reactive hepatitis (via B18.-), K75.3 — Granulomatous hepatitis, not elsewhere classified (via B18.-), K75.9 — Inflammatory liver disease, unspecified (via B18.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 11 Excludes2 notes across 3 chapters: K70 — Alcoholic liver disease (via B18.-), K70-K77 — Diseases of liver (K70-K77) (via B18.-), K71 — Toxic liver disease (via B18.-), K72 — Hepatic failure, not elsewhere classified (via B18.-), K73 — Chronic hepatitis, not elsewhere classified (via B18.-), K74 — Fibrosis and cirrhosis of liver (via B18.-), K75 — Other inflammatory liver diseases (via B18.-), K76 — Other diseases of liver (via B18.-), K77 — Liver disorders in diseases classified elsewhere (via B18.-), T80.6 — Other serum reactions (via B18.-), Z22 — Carrier of infectious disease (via B18.-).

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

Referenced by 2 Code First instructions across 2 chapters: H67 — Otitis media in diseases classified elsewhere (via B18.-), M02 — Postinfective and reactive arthropathies (via B18.-).

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.

Referenced by 1 Code Also instruction: K74 — Fibrosis and cirrhosis of liver (via B18.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 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 40 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 5 MS-DRGs: DRG 441 (MDC 07), DRG 442 (MDC 07), DRG 443 (MDC 07), DRG 791 (MDC 15), DRG 793 (MDC 15).

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

Clinical classification (AHRQ CCSR):INF007 — Hepatitis (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 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.

B17.0 — Acute delta-(super) infection of hepatitis B carrier, B17.10 — Acute hepatitis C without hepatic coma, B17.11 — Acute hepatitis C with hepatic coma, B17.2 — Acute hepatitis E, B17.8 — Other specified acute viral hepatitis, B17.9 — Acute viral hepatitis, unspecified, B18.0 — Chronic viral hepatitis B with delta-agent, B18.1 — Chronic viral hepatitis B without delta-agent, B18.2 — Chronic viral hepatitis C, B18.8 — Other chronic viral hepatitis, B19.0 — Unspecified viral hepatitis with hepatic coma, B19.10 — Unspecified viral hepatitis B without hepatic coma, B19.11 — Unspecified viral hepatitis B with hepatic coma, B19.20 — Unspecified viral hepatitis C without hepatic coma, B19.21 — Unspecified viral hepatitis C with hepatic coma, B19.9 — Unspecified viral hepatitis without hepatic coma, B33.24 — Viral cardiomyopathy, B33.4 — Hantavirus (cardio)-pulmonary syndrome [HPS] [HCPS], B33.8 — Other specified viral diseases, B34.1 — Enterovirus infection, unspecified, +19 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Chronic Hepatitis) for risk-adjusted payment.

B18.0 — Chronic viral hepatitis B with delta-agent, B18.1 — Chronic viral hepatitis B without delta-agent, B18.2 — Chronic viral hepatitis C, B18.8 — Other chronic viral hepatitis, K70.10 — Alcoholic hepatitis without ascites, K70.11 — Alcoholic hepatitis with ascites, K71.3 — Toxic liver disease with chronic persistent hepatitis, K71.4 — Toxic liver disease with chronic lobular hepatitis, K71.50 — Toxic liver disease with chronic active hepatitis without ascites, K71.51 — Toxic liver disease with chronic active hepatitis with ascites, K73.0 — Chronic persistent hepatitis, not elsewhere classified, K73.1 — Chronic lobular hepatitis, not elsewhere classified, K73.2 — Chronic active hepatitis, not elsewhere classified, K73.8 — Other chronic hepatitis, not elsewhere classified, K73.9 — Chronic hepatitis, unspecified, K75.4 — Autoimmune hepatitis

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Liver Transplant Status/Complications, Chronic Liver Failure/End-Stage Liver Disorders, Cirrhosis of Liver

Same clinical category (CCSR)

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

B17.0 — Acute delta-(super) infection of hepatitis B carrier, B17.10 — Acute hepatitis C without hepatic coma, B17.11 — Acute hepatitis C with hepatic coma, B17.2 — Acute hepatitis E, B17.8 — Other specified acute viral hepatitis, B17.9 — Acute viral hepatitis, unspecified, B18.0 — Chronic viral hepatitis B with delta-agent, B18.1 — Chronic viral hepatitis B without delta-agent, B18.2 — Chronic viral hepatitis C, B18.8 — Other chronic viral hepatitis, B19.0 — Unspecified viral hepatitis with hepatic coma, B19.10 — Unspecified viral hepatitis B without hepatic coma, B19.11 — Unspecified viral hepatitis B with hepatic coma, B19.20 — Unspecified viral hepatitis C without hepatic coma, B19.21 — Unspecified viral hepatitis C with hepatic coma, B19.9 — Unspecified viral hepatitis without hepatic coma, B25.1 — Cytomegaloviral hepatitis, B26.81 — Mumps hepatitis, B58.1 — Toxoplasma hepatitis, K70.10 — Alcoholic hepatitis without ascites, +300 more

Same Index main term, other category

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

B16.0 — Acute hepatitis B with delta-agent with hepatic coma (D, acute, with hepatic coma), B16.1 — Acute hepatitis B with delta-agent without hepatic coma (D), B16.2 — Acute hepatitis B without delta-agent with hepatic coma (B, acute, with, hepatic coma), B16.9 — Acute hepatitis B without delta-agent and without hepatic coma (B, acute), B17.0 — Acute delta-(super) infection of hepatitis B carrier (D, acute, in hepatitis B carrier), B17.10 — Acute hepatitis C without hepatic coma (C, acute), B17.11 — Acute hepatitis C with hepatic coma (C, acute, with hepatic coma), B17.2 — Acute hepatitis E (viral, virus, type, E), B17.8 — Other specified acute viral hepatitis (viral, virus, non-A, non-B), B17.9 — Acute viral hepatitis, unspecified (acute), 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), B33.8 — Other specified viral diseases (viral, virus, coxsackie), B58.1 — Toxoplasma hepatitis (in, toxoplasmosis), +57 more

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.

Gamma-glutamyl Transferase (GGT) Test, Hepatitis Testing, HIV Screening Test, Iron Panel, Partial Thromboplastin Time (PTT) Test, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of B18.9 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 B18.9 with these 13 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes (11)

Referenced by Code First instructions

Referenced by Code Also instructions

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 65 — Chronic Hepatitis [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

MDC crossing

  • MDC 07 — Diseases and Disorders of the Hepatobiliary System and Pancreas[MDC crossing]: “Diseases and Disorders of the Hepatobiliary System and Pancreas — 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. 2,488 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

  • Carrierof (suspected), hepatitis (viral)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Hepatitis, infectious, infective, chronic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Hepatitis, viral, virus, chronic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

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 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
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release 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. "B18.9 — Chronic viral hepatitis, unspecified." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/b18.9-chronic-viral-hepatitis-unspecified

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Chronic viral hepatitis, unspecified

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 B18.9 in its code family, with their registry titles.

View all codes in the B18 family