2027 ICD-10-CM Diagnosis Code B18.1Chronic viral hepatitis B without delta-agent
ICD-10-CM Codes›A00–B99›B15-B19›B18
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 65
- Chronic Condition
B18.1 is a billable ICD-10-CM diagnosis code for chronic viral hepatitis B without delta-agent. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 441 through 443, 791, 793. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 40 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hepatitis and Viral infection.
For Medicare Advantage risk adjustment, B18.1 maps to CMS-HCC Category 65 (Chronic Hepatitis) under the V28 model, adding a risk factor of about 0.185 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
B18.1 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chronic active hepatitis
- Chronic active type B viral hepatitis
- Chronic active viral hepatitis
- Chronic aggressive type B viral hepatitis
- Chronic aggressive viral hepatitis
- Chronic hepatitis B co-occurrent with hepatitis C and hepatitis D
- Chronic hepatitis B during pregnancy
- Chronic persistent hepatitis
- Chronic persistent type B viral hepatitis
- Chronic persistent viral hepatitis
- Chronic type B viral hepatitis
- Chronic viral hepatitis B with hepatitis D
- Chronic viral hepatitis B without delta-agent
- Hepatic coma due to chronic hepatitis B
- Hepatic coma due to viral hepatitis
- Hepatic coma due to viral hepatitis B
- Hepatitis B and hepatitis C
- Hepatitis B carrier
- Liver disorder in pregnancy
- Occult chronic type B viral hepatitis
- Viral hepatitis carrier
- Viral hepatitis complicating pregnancy, childbirth and the puerperium
- Viral hepatitis D
- Viral hepatitis in mother complicating pregnancy
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to B18.1: its own notes plus those printed at B18, block B15-B19, and Chapter 1. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- Carrier of viral hepatitis
- diseases generally recognized as communicable or transmissible
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Carrier of viral hepatitis B
- Chronic (viral) hepatitis B
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- sequelae of viral hepatitis (B94.2)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify resistance to antimicrobial drugs (Z16.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name B18.1, its category, or a range that includes it.
Applicable To 1
These notes mention B18.1.
- O98.4 Viral hepatitis complicating pregnancy, childbirth and the puerperium
Excludes1 4
These codes carry an Excludes1 note naming B18.1: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 4
These codes carry an Excludes2 note naming B18.1: its condition is not part of those codes, and both may be reported when the patient has both.
- Z22 Carrier of infectious diseasecarrier of viral hepatitis (B18.-) names B18.-, which includes this code
- Block K70-K77 Diseases of liver
- K72 Hepatic failure, not elsewhere classified
- T80.6 Other serum reactions
Code First 1
These codes say to code first a condition named in the note, and B18.1 is one of the conditions named.
- M02 Postinfective and reactive arthropathies
Use Additional Code 1
These codes say to use an additional code from the note, and B18.1 is one of the codes named.
- C22 Malignant neoplasm of liver and intrahepatic bile ducts
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
hepatitis See Also: Hepatitis, viral, type B;
carrier (suspected) of B18.1
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Chronic Viral Hepatitis
chronic hepatitis caused by viruses, most commonly hepatitis viruses b and c.
Patient EducationClinical
Hepatitis B
Hepatitis is inflammation of the liver. Inflammation is swelling that happens when tissues of the body are injured or infected. It can damage your liver. This swelling and damage can affect how well your liver functions.
The full article covers:
- What is hepatitis?
- What is hepatitis B?
- What causes hepatitis B?
- Who is at risk for hepatitis B?
- What are the symptoms of hepatitis B?
- What other problems can hepatitis B cause?
- How is hepatitis B diagnosed?
- What are the treatments for hepatitis B?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert B18.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About B18.1Overview
What is the ICD-10 code for chronic viral hepatitis B without delta-agent?
The ICD-10-CM code for chronic viral hepatitis B without delta-agent is B18.1 (sometimes written as B181). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is B18.1 (Chronic viral hepatitis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report chronic viral hepatitis B without delta-agent on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does B18.1 group to?
When chronic viral hepatitis B without delta-agent is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 442, 441, 443, with relative weights from 0.6890 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is B18.1 a CC or MCC?
CMS lists B18.1 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 40 closely related codes in its exclusion list.
Can B18.1 be reported with B94.2?
Not as a rule. The Excludes1 note at block B15-B19, which applies to B18.1, lists "sequelae of viral hepatitis (B94.2)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What HCC is B18.1?
B18.1 (chronic viral hepatitis B without delta-agent) maps to CMS-HCC Category 65 (Chronic Hepatitis), commonly written as HCC 65, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 29 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 56.
Does B18.1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, B18.1 adds a risk adjustment factor of about 0.185 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.101 to 0.378 depending on the payment segment). A more severe related category (HCC 62, HCC 63, and HCC 64) supersedes it when both are reported. See the full factor table on the HCC 65 category page.
