2024 ICD-10-CM Diagnosis Code A09

Infectious gastroenteritis and colitis, unspecified

ICD-10-CM Code:
A09
ICD-10 Code for:
Infectious gastroenteritis and colitis, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Certain infectious and parasitic diseases
    (A00–B99)
    • Intestinal infectious diseases
      (A00-A09)
      • Infectious gastroenteritis and colitis, unspecified
        (A09)

A09 is a billable diagnosis code used to specify a medical diagnosis of infectious gastroenteritis and colitis, 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 A09 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:

  • Acute erosive gastritis
  • Acute gastroenteritis
  • Acute gastroenteritis
  • Acute gastroenteritis
  • Acute gastroenteritis
  • Acute infectious nonbacterial gastroenteritis
  • Acute infective gastroenteritis
  • Acute ulcerative gastroenteritis complicating pneumonia
  • Aspergillosis enteritis of intestine
  • Aspergillosis enteritis of intestine
  • Aspergillus colitis
  • Blastomycotic enteritis of intestine
  • Catarrhal dysentery
  • Colitis presumed infectious
  • Colitis, enteritis and gastroenteritis presumed infectious
  • Diarrhea of presumed infectious origin
  • Disease due to superfamily Heterocheiloidea
  • Disease of presumed infectious origin
  • Disease of presumed infectious origin
  • Disease of presumed infectious origin
  • Disease of presumed infectious origin
  • Disease of presumed infectious origin
  • Disorder of gastrointestinal tract co-occurrent with human immunodeficiency virus infection
  • Disorder of gastrointestinal tract co-occurrent with human immunodeficiency virus infection
  • Dysenteric diarrhea
  • Enteritis of intestine presumed infectious
  • Enteritis of small intestine presumed infectious
  • Epidemic diarrhea
  • Epidemic gastroenteritis
  • Erosive gastritis
  • Fungal colitis
  • Fungal colitis
  • Fungal duodenitis
  • Fungal gastrointestinal infection
  • Gastroenteritis presumed infectious
  • Gastrointestinal infection
  • Herpes simplex gastrointestinal tract infection
  • Infection by Anisakidae
  • Infection by Anisakis larva
  • Infection by Blastomyces dermatitidis
  • Infection of digestive system
  • Infection of intestine caused by Anisakis larva
  • Infection of large intestine
  • Infectious colitis
  • Infectious diarrheal disease
  • Infectious disease of digestive tract
  • Infectious enteritis of intestine
  • Infectious gastroenteritis
  • Infectious gastroenteritis co-occurrent with human immunodeficiency virus infection
  • Infectious gastroenteritis co-occurrent with human immunodeficiency virus infection
  • Infectious gastroenteritis with AIDS
  • Infective gastritis
  • Inflammatory diarrhea
  • Institution-acquired gastroenteritis
  • Institutional environment related disease
  • Intestinal infectious disease
  • Phlegmonous enteritis of gastrointestinal tract
  • Purulent enteritis
  • Secondary acquired megacolon
  • Suppurative gastritis
  • Toddler diarrhea
  • Toxic megacolon due to infectious colitis
  • Toxic state

Clinical Classification

Clinical CategoryCCSR Category CodeInpatient Default CCSROutpatient Default CCSR
Intestinal infectionDIG001Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.
Parasitic, other specified and unspecified infectionsINF009N - Not default inpatient assignment for principal diagnosis or first-listed diagnosis.N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.

Clinical Information

  • Erosive Gastritis

    gastritis that is characterized by erosion of the mucosal surface.
  • Infectious Colitis

    a viral or bacterial infectious process affecting the large intestine.

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.


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Infectious colitis NOS
  • Infectious enteritis NOS
  • Infectious gastroenteritis NOS

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.
  • colitis NOS K52.9
  • diarrhea NOS R19.7
  • enteritis NOS K52.9
  • gastroenteritis NOS K52.9
  • noninfective gastroenteritis and colitis, unspecified K52.9

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 A09 to ICD-9-CM

  • ICD-9-CM Code: 009.0 - Infectious enteritis 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


Gastroenteritis

What is gastroenteritis?

Gastroenteritis is an inflammation of the lining of the stomach and intestines. The main symptoms include vomiting and diarrhea. It is usually not serious in healthy people, but it can sometimes lead to dehydration or cause severe symptoms.

What causes gastroenteritis?

There can be many different causes of gastroenteritis:

  • Viruses
  • Bacteria
  • Parasites
  • Chemicals
  • Reactions to certain medicines and food

Viral gastroenteritis is the most common type. It can be caused by many different viruses, including noroviruses and rotaviruses. Some people call viral gastroenteritis the "stomach flu." But this name is not medically correct. It is not caused by flu viruses. The flu is a respiratory infection that affects your nose, throat and lungs.

When gastroenteritis is caused by consuming foods or drinks contaminated with viruses, bacteria, parasites, or chemicals, this is called food poisoning.

The viruses, bacteria, and parasites that cause gastroenteritis can also spread from person to person. You could be infected when you touch something that has the germs on it and then touch your eyes, mouth, or nose.

What are the symptoms of gastroenteritis?

The symptoms of gastroenteritis include:

  • Diarrhea
  • Pain or cramping in your abdomen (belly)
  • Nausea
  • Vomiting
  • Sometimes fever

Gastroenteritis is usually not serious. But it can sometimes cause lead to dehydration or cause severe symptoms. Certain people are at higher risk for these problems. They include:

  • Pregnant women
  • Older adults
  • People with weakened immune systems or other serious health conditions
  • Infants
  • Babies who were born prematurely or have other health conditions

If you or a family member are at higher risk and have symptoms of gastroenteritis, contact a health care provider right away. Even if you are not at high risk, it is possible to become dehydrated or have more serious symptoms. There are some warning signs to watch for. It's important to contact a provider right away if you or your child have any of them:

  • For adults, they include:
    • Change in mental state, such as irritability or lack of energy
    • Diarrhea lasting more than 2 days
    • High fever
    • Vomiting often
    • Six or more loose stools in a day
    • Severe pain in the abdomen (belly) or rectum
    • Stools that are black and tarry or contain blood or pus
    • Symptoms of dehydration, such as thirst, dry mouth, headache, dark-colored urine, and urinating less than normal

  • For infants and children, they include:
    • Change in the child's mental state, such as irritability or lack of energy
    • Diarrhea lasting more than a day
    • Any fever in infants
    • High fever in older children
    • Frequent loose stools
    • Vomiting often
    • Severe pain in the abdomen (belly) or rectum
    • Signs or symptoms of dehydration, such as thirst, dry mouth, urinating less than usual or no wet diapers for 3 hours or more, and no tears when crying
    • Stools that are black and tarry or contain blood or pus

How is gastroenteritis diagnosed?

To find out if you have gastroenteritis, your provider:

  • Will do a physical exam
  • Will ask about your symptoms
  • May do tests of your stool

What are the treatments for gastroenteritis?

Usually, people with gastroenteritis get better on their own, with rest and plenty of fluids and electrolytes. Your provider may suggest that you take a probiotic. Studies suggest that some probiotics may help shorten a case of diarrhea.

People with more severe symptoms may need medicines to control nausea or vomiting. Providers may also give other medicines for certain types of gastroenteritis, such as antibiotics for some bacterial types and antiparasitic medicines for some parasitic types.

Can gastroenteritis be prevented?

Gastroenteritis cannot always be prevented. But proper hand washing, cleaning surfaces that may be infected with germs, and safe food preparation may help prevent some of the infections that can cause gastroenteritis. There are vaccines for infants to protect against rotavirus infections.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases


[Learn More in MedlinePlus]

Infectious Diseases

What are infectious diseases?

Germs, or microbes, are found everywhere - in the air, soil, and water. There are also germs on your skin and in your body. Many of them are harmless, and some can even be helpful. But some of them can make you sick. Infectious diseases are diseases that are caused by germs.

What are the different types of germs that cause infectious diseases?

There are four main types of germs:

  • Bacteria are one-celled germs that multiply quickly. They may give off toxins, which are harmful chemicals that can make you sick. Strep throat and urinary tract infections are common bacterial infections.
  • Viruses are tiny capsules that contain genetic material. They invade your cells so that they can multiply. This can kill, damage, or change the cells and make you sick. Viral infections include HIV and the common cold.
  • Fungi are primitive plant-like organisms such as mushrooms, mold, mildew, and yeasts. Athlete's foot and yeast infections are common fungal infections.
  • Parasites are animals or plants that survive by living on or in other living things. Malaria and head lice are infections that are caused by parasites.

How can you get infectious diseases?

There are many different ways that you can get an infectious disease:

  • Through direct contact with a person who is sick. This includes kissing, touching, sneezing, coughing, and sexual contact. Pregnant people can also pass some germs along to their babies.
  • Through indirect contact, when you touch something that has germs on it. For example, you could get germs if someone who is sick touched a door handle, and then you touch it.
  • Through insect or animal bites.
  • Through contaminated food, water, soil, or plants.

What are the symptoms of infectious diseases?

Infectious diseases can cause many different symptoms. Some are so mild that you may not even notice any symptoms, while others can be life-threatening.

What are the treatments for infectious diseases?

There are treatments for some infectious diseases, such as antibiotic, antiviral, antifungal and anti-parasitic medicines. But for other infections, such as some caused by viruses, you can only treat your symptoms.

Can infectious diseases be prevented?

You can take steps to prevent many infectious diseases:

  • Get vaccinated
  • Wash your hands often
  • Pay attention to food safety
  • Avoid contact with wild animals
  • Practice safe sex (use a condom every time you have anal, vaginal, or oral sex)
  • Don't share items such as toothbrushes, combs, and straws

[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.

Footnotes

[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.