2024 ICD-10-CM Diagnosis Code R18.0

Malignant ascites

ICD-10-CM Code:
ICD-10 Code for:
Malignant ascites
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Code Navigator:

Code Classification

  • Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
    • Symptoms and signs involving the digestive system and abdomen
      • Ascites

R18.0 is a billable diagnosis code used to specify a medical diagnosis of malignant ascites. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

This code describes a circumstance which influences the patient's health status but not a current illness or injury. The code is unacceptable as a principal diagnosis.

According to ICD-10-CM guidelines this code should not to be used as a principal diagnosis code when a related definitive diagnosis has been established.

Approximate Synonyms

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

  • Ascitic fluid examination abnormal
  • Ascitic fluid: malignant cells
  • Malignant ascites
  • Peritoneal fluid abnormal

Clinical Classification

Clinical CategoryCCSR Category CodeInpatient Default CCSROutpatient Default CCSR
Abdominal pain and other digestive/abdomen signs and symptomsSYM006X - Not applicable.N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.
Conditions due to neoplasm or the treatment of neoplasmNEO074X - Not applicable.Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Clinical Information

  • Ascites

    accumulation or retention of free fluid within the peritoneal cavity.
  • Carcinoma, Ehrlich Tumor

    a transplantable, poorly differentiated malignant tumor which appeared originally as a spontaneous breast carcinoma in a mouse. it grows in both solid and ascitic forms.
  • Chylous Ascites

    presence of milky lymph (chyle) in the peritoneal cavity, with or without infection.
  • Mucin-4

    a transmembrane mucin that is found in a broad variety of epithelial tissue. mucin-4 may play a role in regulating cellular adhesion and in cell surface signaling from the erbb-2 receptor protein-tyrosine kinase. mucin-4 is a heterodimer of alpha and beta chains. the alpha and beta chains result from the proteolytic cleavage of a precursor protein.
  • Peritoneovenous Shunt

    an operation for the continuous emptying of ascitic fluid into the venous system. fluid removal is based on intraperitoneal and intrathoracic superior vena cava pressure differentials and is performed via a pressure-sensitive one-way valve connected to a tube traversing the subcutaneous tissue of the chest wall to the neck where it enters the internal jugular vein and terminates in the superior vena cava. it is used in the treatment of intractable ascites.
  • Pseudomyxoma Peritonei

    a peritoneal adenocarcinoma characterized by build-up of mucus in the peritoneal cavity. mucus secreting cells may attach to the peritoneal lining and continue to secrete mucus. the majority of cases represent tumor spread from a primary low-grade mucinous neoplasm of the appendix (nci thesaurus).
  • Receptor, ErbB-2

    a cell surface protein-tyrosine kinase receptor that is overexpressed in a variety of adenocarcinomas. it has extensive homology to and heterodimerizes with the egf receptor, the erbb-3 receptor, and the erbb-4 receptor. activation of the erbb-2 receptor occurs through heterodimer formation with a ligand-bound erbb receptor family member.

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.
  • malignancy, such as:
  • malignant neoplasm of ovary C56
  • secondary malignant neoplasm of retroperitoneum and peritoneum C78.6

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).

Code Edits

The Medicare Code Editor (MCE) detects and reports errors in the coding of claims data. The following ICD-10-CM Code Edits are applicable to this code:

  • Unacceptable principal diagnosis - There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Convert R18.0 to ICD-9-CM

  • ICD-9-CM Code: 789.51 - Malignant ascites

Patient Education

Liver Diseases

Your liver is the largest organ inside your body. It helps your body digest food, store energy, and remove poisons.

There are many kinds of liver diseases:

  • Diseases caused by viruses, such as hepatitis A, hepatitis B, and hepatitis C
  • Diseases caused by drugs, poisons, or too much alcohol. Examples include fatty liver disease and cirrhosis.
  • Liver cancer
  • Inherited diseases, such as hemochromatosis and Wilson disease

Symptoms of liver disease can vary, but they often include swelling of the abdomen and legs, bruising easily, changes in the color of your stool and urine, and jaundice, or yellowing of the skin and eyes. Sometimes there are no symptoms. Tests such as imaging tests and liver function tests can check for liver damage and help to diagnose liver 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] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.