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  6. 2025 ICD-10-CM Code J18

2025 ICD-10-CM Diagnosis Code J18

Pneumonia, unspecified organism

ICD-10-CM Code:
J18
ICD-10 Code for:
Pneumonia, unspecified organism
Is Billable?
Not Valid for Submission
Code Navigator:

J18 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of pneumonia, unspecified organism. The code is not specific and is NOT valid for the year 2025 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Unspecified diagnosis codes like J18 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.

Specific Coding Applicable to Pneumonia, unspecified organism

Non-specific codes like J18 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for pneumonia, unspecified organism:

  • Use J18.0 for Bronchopneumonia, unspecified organism - BILLABLE CODE

  • Use J18.1 for Lobar pneumonia, unspecified organism - BILLABLE CODE

  • Use J18.2 for Hypostatic pneumonia, unspecified organism - BILLABLE CODE

  • Use J18.8 for Other pneumonia, unspecified organism - BILLABLE CODE

  • Use J18.9 for Pneumonia, unspecified organism - BILLABLE CODE

Code Classification

  • Diseases of the respiratory system
    J00–J99
    • Influenza and pneumonia
      J09-J18
      • Pneumonia, unspecified organism
        J18

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.


Code First

Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.

Code Also

Code Also
A "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.
  • , if applicable, any associated condition such as:
  • aspiration pneumonia J69

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.
  • congenital pneumonia P23.0
  • drug-induced interstitial lung disorder J70.2 J70.4
  • interstitial pneumonia NOS J84.9
  • neonatal aspiration pneumonia P24
  • pneumonitis due to fumes and vapors J68.0
  • usual interstitial pneumonia J84.178

Type 2 Excludes

Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
  • abscess of lung with pneumonia J85.1
  • aspiration pneumonia due to anesthesia during labor and delivery O74.0
  • aspiration pneumonia due to anesthesia during pregnancy O29
  • aspiration pneumonia due to anesthesia during puerperium O89.0
  • aspiration pneumonia due to solids and liquids J69
  • aspiration pneumonia NOS J69.0
  • lipid pneumonia J69.1
  • pneumonitis due to external agents J67 J70

Patient Education


Pneumonia

What is pneumonia?

Pneumonia is an infection in one or both of your lungs. It causes the air sacs of your lungs to fill up with fluid or pus. Pneumonia can range from mild to severe, depending on what caused it, your age, and your overall health.

What causes pneumonia?

Bacterial, viral, and fungal infections can cause pneumonia.

Bacteria are the most common cause. Bacterial pneumonia can occur on its own. It can also develop after you've had certain viral infections such as a cold or the flu. Several different types of bacteria can cause pneumonia, including:

  • Streptococcus pneumoniae
  • Legionella pneumophila; this type of pneumonia is often called Legionnaires' disease
  • Mycoplasma pneumoniae
  • Chlamydia pneumoniae
  • Haemophilus influenzae type b (Hib)

Viruses that infect the respiratory tract may cause pneumonia. Viral pneumonia is often mild and goes away on its own within a few weeks. But sometimes it is serious enough that you need to get treatment in a hospital. If you have viral pneumonia, you are at risk of also getting bacterial pneumonia. The different viruses that can cause pneumonia include:

  • Respiratory syncytial virus (RSV)
  • Some common cold and flu viruses
  • SARS-CoV-2, the virus that causes COVID-19

Fungal pneumonia is more common in people who have chronic health problems or weakened immune systems. Some of the types include:

  • Pneumocystis pneumonia (PCP)
  • Valley fever (Coccidioidomycosis)
  • Histoplasmosis
  • Cryptococcal pneumonia

Aspiration can also cause pneumonia. It can happen when you aspirate (accidentally breathe in) food or fluid into the lungs. If you are not able to cough out the food or fluid, it may cause an infection.

Who is more likely to develop pneumonia?

Anyone can develop pneumonia, but certain factors can increase your risk:

  • Age; the risk is higher for children who are age 2 and under and adults age 65 and older.
  • Exposure to certain chemicals, pollutants, or toxic fumes.
  • Lifestyle habits, such as smoking, heavy alcohol use, and malnourishment.
  • Being in a hospital, especially if you are in the ICU. Being sedated and/or on a ventilator raises the risk even more.
  • Having a lung disease.
  • Having a weakened immune system.
  • Have trouble coughing or swallowing, from a stroke or other condition.
  • Recently having been sick with a cold or the flu.
  • Other chronic (long-lasting) health conditions, including diabetes, heart failure, sickle cell disease, liver disease, and kidney disease.

What are the symptoms of pneumonia?

The symptoms of pneumonia can range from mild to severe and include:

  • Fever
  • Chills
  • Cough, usually with phlegm (a type of thick mucus made in your lungs)
  • Shortness of breath
  • Chest pain when you breathe or cough
  • Nausea and/or vomiting
  • Diarrhea

The symptoms can vary for different groups. Newborns and infants may not show any signs of the infection. Others may vomit and have a fever and cough. They might seem sick, with no energy, or be restless.

Older adults and people who have serious illnesses or weak immune systems may have fewer and milder symptoms. They may even have a lower-than-normal temperature. Older adults who have pneumonia sometimes may feel weak or suddenly get confused.

What other problems can pneumonia cause?

Sometimes pneumonia can cause serious complications such as:

  • Bacteremia, which happens when the bacteria move into the bloodstream. It is serious and can lead to septic shock.
  • Lung abscesses, which are collections of pus in cavities of the lungs.
  • Pleural disorders, which are conditions that affect the pleura. The pleura is the tissue that covers the outside of the lungs and lines the inside of your chest cavity.
  • Kidney failure.
  • Respiratory failure.

How is pneumonia diagnosed?

Sometimes pneumonia can be hard to diagnose. This is because it can cause some of the same symptoms as a cold or the flu. It may take time for you to realize that you have a more serious condition.

To find out if you have pneumonia, your health care provider:

  • Will take your medical history, which includes asking about your symptoms
  • Will do a physical exam, which includes listening to your lungs with a stethoscope
  • May order various tests, such as:
    • A chest x-ray
    • Blood tests such as a complete blood count (CBC) to see if your immune system is actively fighting an infection
    • A blood culture to find out whether you have a bacterial infection that has spread to your bloodstream

If you are in the hospital, have serious symptoms, are older, or have other health problems, you may also have more tests, such as:

  • Sputum test, which checks for bacteria in a sample of your sputum (mucus that is brought up from the lungs by coughing).
  • Chest CT scan to see how much of your lungs are affected. It may also show if you have complications such as lung abscesses or pleural effusions (a buildup of fluid in the pleural space).
  • Pleural fluid culture, which checks for bacteria in a fluid sample that was taken from the pleural space.
  • Pulse oximetry or blood oxygen level test, to check how much oxygen is in your blood.
  • Bronchoscopy, a procedure used to look inside your lungs' airways.

What are the treatments for pneumonia?

Treatment for pneumonia depends on the type of pneumonia, which germ is causing it, and how severe it is:

  • Antibiotics treat bacterial pneumonia and some types of fungal pneumonia. They do not work for viral pneumonia.
  • In some cases, your provider may prescribe antiviral medicines for viral pneumonia.
  • Antifungal medicines treat other types of fungal pneumonia.

You may need to be treated in a hospital if your symptoms are severe or if you are at risk for complications. While there, you may get additional treatments. For example, if your blood oxygen level is low, you may receive oxygen therapy.

It may take time to recover from pneumonia. Some people feel better within a week. For other people, it can take a month or more.

Can pneumonia be prevented?

Vaccines can help prevent pneumonia caused by pneumococcal bacteria or the flu virus. Washing your hands often, not smoking, and having a healthy lifestyle may also help prevent pneumonia.

NIH: National Heart, Lung, and Blood Institute


[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.