R18.0 – Malignant ascites

ICD-10-CM 2027 diagnosis code · Symptoms and signs involving the digestive system and abdomen

Billable code

ICD-10-CM code R18.0

Code: R18.0 (claims format: R180)
Description: Malignant ascites
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 18. Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
Block: R10-R19 Symptoms and signs involving the digestive system and abdomen
Parent codes: R18

Notes for R18.0

Code first:

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

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

R18 – Ascites

Includes:

fluid in peritoneal cavity

Excludes1 (not coded here):

ascites in alcoholic cirrhosis (K70.31)
ascites in alcoholic hepatitis (K70.11)
ascites in toxic liver disease with chronic active hepatitis (K71.51)

Block R10-R19

Excludes2 (not included here):

congenital or infantile pylorospasm (Q40.0)
gastrointestinal hemorrhage (K92.0-K92.2)
intestinal obstruction (K56.-)
newborn gastrointestinal hemorrhage (P54.0-P54.3)
newborn intestinal obstruction (P76.-)
pylorospasm (K31.3)
signs and symptoms involving the urinary system (R30-R39)
symptoms referable to female genital organs (N94.-)
symptoms referable to male genital organs (N48-N50)

Index terms for R18.0

Entries in the ICD-10-CM alphabetic index that lead to this code:

Ascites, malignant

Related codes in R18

R18.8 – Other ascitesBillable

Frequently asked questions

What is ICD-10 code R18.0?

R18.0 is the ICD-10-CM code for malignant ascites, in the block R10-R19 (Symptoms and signs involving the digestive system and abdomen).

Is R18.0 a billable code?

Yes. R18.0 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does R18.0 belong to?

It belongs to category R18 – Ascites.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.