2027 ICD-10-CM Diagnosis Code B01Varicella [chickenpox]

ICD-10-CM Codes›A00–B99›B00-B09›B01

ICD-10-CM B01
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

B01 is a non-billable ICD-10-CM category code for varicella [chickenpox], so it cannot be submitted on claims. Use a more specific code from this category instead, such as B01.0, B01.11, B01.12, and B01.2.

Code Identity

ICD-10-CM Code
B01
Billable Status
No — Non-Billable Category
Code Describes
Varicella [chickenpox]
Short Description
Varicella [chickenpox]
Same as the full description in the CMS dataset.
Chapter
B00-B09
Viral infections characterized by skin and mucous membrane lesions

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB00-B09Viral infections characterized by skin and mucous membrane lesions
CategoryB01Varicella [chickenpox]
This CodeB01Varicella [chickenpox]

Specific Coding for Varicella [chickenpox]Overview

Non-specific codes like B01 require more characters. Use one of these billable codes instead:

  • Use B01.0 for Varicella meningitis

  • B01.1 for Varicella encephalitis, myelitis and encephalomyelitis

  • Use B01.11 for Varicella encephalitis and encephalomyelitis

  • Use B01.12 for Varicella myelitis

  • Use B01.2 for Varicella pneumonia

  • B01.8 for Varicella with other complications

  • Use B01.81 for Varicella keratitis

  • Use B01.89 for Other varicella complications

  • Use B01.9 for Varicella without complication

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to B01: its own notes plus those printed at 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.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

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.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • 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.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • 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 B01, its category, or a range that includes it.

Excludes2 2

These codes carry an Excludes2 note naming B01: its condition is not part of those codes, and both may be reported when the patient has both.

  • B10 Other human herpesviruses
    human herpesvirus 3 (B01.-, B02.-)
  • B10 Other human herpesviruses
    varicella (B01.-)

Patient EducationClinical

Chickenpox

Chickenpox is an infection caused by the varicella-zoster virus. Most cases are in children under age 15, but older children and adults can get it. It spreads very easily from one person to another.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About B01Overview

What is the ICD-10 code for varicella [chickenpox]?

B01 is the ICD-10-CM category for varicella [chickenpox], but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is B01 (Varicella [chickenpox]) a billable code?

No. This is a category header that groups the codes for varicella [chickenpox], and headers cannot be submitted on claims. Claims for varicella [chickenpox] need a more specific code from this category, such as B01.0, B01.11, and B01.12.