2027 ICD-10-CM Diagnosis Code B05.9Measles without complication

ICD-10-CM Codes›A00–B99›B00-B09›B05

ICD-10-CM B05.9
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

B05.9 is a billable ICD-10-CM diagnosis code for measles without complication. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 865 through 866. Coders also document this condition as exanthem caused by Measles morbillivirus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Viral infection.

Code Identity

ICD-10-CM Code
B05.9
Billable Status
Yes — Valid for Submission
Code Describes
Measles without complication
Short Description
Measles without complication
Same as the full description in the CMS dataset.
Parent Code
B05
Measles

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB00-B09Viral infections characterized by skin and mucous membrane lesions
CategoryB05Measles
This CodeB05.9Measles without complication

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Exanthem caused by Measles morbillivirus
  • Koplik spots
  • Measles
  • Modified measles

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to B05.9: its own notes plus those printed at B05 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.

From B05 Measles applies to 8 codes
  • morbilli
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • 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.

  • Measles NOS

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From B05 Measles applies to 8 codes
  • subacute sclerosing panencephalitis (A81.1)

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.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF008
Viral infection
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Measles

    a highly contagious infectious disease caused by morbillivirus, common among children but also seen in the nonimmune of any age, in which the virus enters the respiratory tract via droplet nuclei and multiplies in the epithelial cells, spreading throughout the mononuclear phagocyte system.

Patient EducationClinical

Measles

Measles is an infectious disease caused by a virus. It spreads easily from person to person. It causes a blotchy red rash. The rash often starts on the head and moves down the body. Other symptoms include:

Read the full article at MedlinePlus

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

Convert B05.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
055.9 Measles uncomplicated
Exact Match The mapping is direct, with no qualifiers.

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 B05.9Overview

What is the ICD-10 code for measles without complication?

The ICD-10-CM code for measles without complication is B05.9 (sometimes written as B059). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is B05.9 (Measles) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report measles without complication on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does B05.9 group to?

When measles without complication is the principal diagnosis on an inpatient stay, it groups to MS-DRG 866, 865, with relative weights from 0.8691 to 1.3153 depending on complications. Higher weights mean higher Medicare reimbursement.

Can B05.9 be reported with A81.1?

Not as a rule. The Excludes1 note at B05, which applies to B05.9, lists "subacute sclerosing panencephalitis (A81.1)". 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 is the ICD-9 equivalent of B05.9?

Under the General Equivalence Mappings, measles without complication converts to ICD-9-CM 055.9 (measles uncomplicated). The mapping is a direct match.