2027 ICD-10-CM Diagnosis Code A49Bacterial infection of unspecified site

ICD-10-CM Codes›A00–B99›A30-A49›A49

ICD-10-CM A49
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A49 is a non-billable ICD-10-CM category code for bacterial infection of unspecified site, so it cannot be submitted on claims. Use a more specific code from this category instead, such as A49.01, A49.02, A49.1, and A49.2.

Code Identity

ICD-10-CM Code
A49
Billable Status
No — Non-Billable Category
Code Describes
Bacterial infection of unspecified site
Short Description
Bacterial infection of unspecified site
Same as the full description in the CMS dataset.
Chapter
A30-A49
Other bacterial diseases

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA30-A49Other bacterial diseases
CategoryA49Bacterial infection of unspecified site
This CodeA49Bacterial infection of unspecified site

Specific Coding for Bacterial infection of unspecified siteOverview

Non-specific codes like A49 require more characters. Use one of these billable codes instead:

  • A49.0 for Staphylococcal infection, unspecified site

  • Use A49.01 for Methicillin susceptible Staphylococcus aureus infection, unspecified site

  • Use A49.02 for Methicillin resistant Staphylococcus aureus infection, unspecified site

  • Use A49.1 for Streptococcal infection, unspecified site

  • Use A49.2 for Hemophilus influenzae infection, unspecified site

  • Use A49.3 for Mycoplasma infection, unspecified site

  • Use A49.8 for Other bacterial infections of unspecified site

  • Use A49.9 for Bacterial infection, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A49: 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

Excludes1

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

  • bacterial agents as the cause of diseases classified elsewhere (B95-B96)
  • meningococcal infection NOS (A39.9)
  • rickettsial infection NOS (A79.9)
  • spirochetal infection NOS (A69.9)

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.

On A49 itself
  • chlamydial infection NOS (A74.9)
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.

Patient EducationClinical

Bacterial Infections

Bacteria are tiny organisms (living things) that have only one cell. Under a microscope, they look like balls, rods, or spirals. They can be found almost everywhere on Earth. There are lots of bacteria in and on your body. In fact, your body has about 10 times more bacteria cells than human cells.

The full article covers:

  • What are bacteria?
  • How do bacterial infections spread?
  • What are the treatments for bacterial infections?
  • Can bacterial infections be prevented?

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 A49Overview

What is the ICD-10 code for bacterial infection of unspecified site?

A49 is the ICD-10-CM category for bacterial infection of unspecified site, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is A49 (Bacterial infection of unspecified site) a billable code?

No. This is a category header that groups the codes for bacterial infection of unspecified site, and headers cannot be submitted on claims. Claims for bacterial infection of unspecified site need a more specific code from this category, such as A49.01, A49.02, and A49.1.

Can A49 be reported with A39.9?

Not as a rule. The Excludes1 note on A49 lists "meningococcal infection NOS (A39.9)". 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).