2024 ICD-10-CM Diagnosis Code A49.9

Bacterial infection, unspecified

ICD-10-CM Code:
ICD-10 Code for:
Bacterial infection, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Certain infectious and parasitic diseases
    • Other bacterial diseases
      • Bacterial infection of unspecified site

A49.9 is a billable diagnosis code used to specify a medical diagnosis of bacterial infection, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Unspecified diagnosis codes like A49.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Abscess of aortic valve
  • Abscess of mitral valve
  • Abscess of pulmonary valve
  • Acne with gram negative folliculitis
  • Acute bacterial otitis externa
  • Acute bacterial tubulointerstitial nephritis
  • Acute infectious tubulointerstitial nephritis
  • Acute infective otitis externa
  • Acute pyelonephritis
  • Acute pyelonephritis caused by bacterium
  • Acute tubulointerstitial nephritis
  • Angular cheilitis
  • Angular cheilitis due to bacterial infection
  • Autoinflammatory syndrome with pyogenic bacterial infection and amylopectinosis
  • Bacterial abscess of aortic valve
  • Bacterial abscess of mitral valve
  • Bacterial abscess of pulmonary valve
  • Bacterial cellulitis
  • Bacterial corneal ulcer
  • Bacterial encephalitis
  • Bacterial endophthalmitis
  • Bacterial esophagitis
  • Bacterial folliculitis
  • Bacterial genital infection
  • Bacterial infection associated with peritoneal dialysis catheter
  • Bacterial infection due to human immunodeficiency virus infection
  • Bacterial infection of central nervous system
  • Bacterial infection of skin
  • Bacterial infectious disease
  • Bacterial musculoskeletal infection
  • Bacterial nephritis
  • Bacterial oral infection
  • Bacterial osteomyelitis
  • Bacterial otitis media
  • Bacterial respiratory infection
  • Bacterial sinusitis
  • Bacterial tenosynovitis
  • Bacterial tonsillitis
  • Bacterial upper respiratory infection
  • Bacterial urogenital infection
  • Beta lactam resistant bacterial infection
  • Botryomycosis
  • Cutaneous reaction caused by bacterial toxin
  • Disease due to Gram-negative bacteria
  • Erythema nodosum caused by Bacteria
  • Gram-negative bacterial cellulitis
  • Gram-negative folliculitis
  • Gram-negative folliculitis
  • Herpes zoster with secondary bacterial infection
  • Infection - non-suppurative
  • Infection associated with peritoneal dialysis catheter
  • Infection caused by multi drug resistant bacteria
  • Infection due to anaerobic bacteria
  • Infection due to carbapenem resistant bacteria
  • Infection due to quinolone and fluoroquinolone resistant bacteria
  • Infection due to resistant bacteria
  • Infective panniculitis
  • Moderate cavitated lesion limited to outer half of dentin
  • Neonatal hyperbilirubinemia due to bacterial infection
  • Neuropathy due to bacterial toxin
  • Non-pyogenic bacterial infection of skin
  • Peripheral neuropathy caused by toxin
  • Pleural effusion due to bacterial infection
  • Pyogenic bacterial infection due to deficiency of myeloid differentiation primary response 88
  • Recurrent bacterial infection
  • Superficial bacterial infection of skin
  • Toxic polyneuropathy

Clinical Classification

Clinical Information

  • Bacterial Esophagitis

    an acute bacterial infection that affects the esophagus. symptoms include severe pain on swallowing and retrosternal pain. endoscopic examination reveals esophageal mucosal ulcerations and pseudomembranous formations.
  • Acute Pyelonephritis

    sudden onset pyelonephritis.
  • Toxic Polyneuropathy

    polyneuropathy that is caused by exposure to toxins.

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Convert A49.9 to ICD-9-CM

  • ICD-9-CM Code: 041.9 - Bacterial infection NOS
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Patient Education

Bacterial Infections

Bacteria are living things that have only one cell. Under a microscope, they look like balls, rods, or spirals. They are so small that a line of 1,000 could fit across a pencil eraser. Most types of don't make you sick. Many types are helpful. Some of them help to digest food, destroy disease-causing cells, and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt and cheese.

But infectious bacteria can make you ill. They reproduce quickly in your body. Many give off chemicals called toxins, which can damage tissue and make you sick. Examples of bacteria that cause infections include Streptococcus, Staphylococcus, and E. coli.

Antibiotics are the usual treatment. When you take antibiotics, follow the directions carefully. Each time you take antibiotics, you increase the chances that bacteria in your body will learn to resist them causing antibiotic resistance. Later, you could get or spread an infection that those antibiotics cannot cure.

NIH: National Institute of Allergy and Infectious Diseases

[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.


[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.