Is ICD-10-CM code R18 billable?

No, R18 (Ascites) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code R18 belong to?

R18 belongs to Chapter 18 of the ICD-10-CM tabular list: R00–R99 (Symptoms, Signs and Abnormal Clinical and Laboratory Findings).

R18Not billable, use a more specific code below

Ascites

In Symptoms and signs involving the digestive system and abdomen (R10-R19), chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings

2 billable codes under R18: all are a CC; 1 map to HCC 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Includes: conditions that are coded here

fluid in peritoneal cavity

Excludes1: not coded here, use a different code

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

Also applies, from Symptoms and signs involving the digestive system and abdomen (R10-R19)

These notes sit on R10-R19 and apply to every code under it, including R18.

Excludes2: not included here, code separately if applicable

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)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers when to report symptom, sign, and abnormal finding codes (R00-R99), plus specific rules for falls, coma scales, non-infectious SIRS, death NOS, and NIHSS scores.

Use of symptom codes (page 75)
Use of a symptom code with a definitive diagnosis code (page 75)
Combination codes that include symptoms (page 75)
Repeated falls (page 76)
Coma (page 76)
Functional quadriplegia (page 76)
SIRS due to Non-Infectious Process (page 77)
Death NOS (page 77)

Read Section I.C.18 (page 75), 1 more topics

All codes under R18

R18 can't be used on a claim. Pick a billable code below; grey headings group them.

R18 MS-DRGs

As the principal diagnosis, all 2 billable codes under R18 group to MS-DRG 947 or 948 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Other codes that refer to R18

Notes on these codes point to R18.

K66 Excludes2: ascites (R18.-)
R19.0 Excludes1: ascites (R18.-)
R60 Excludes1: ascites (R18.-)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

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:

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.