R18.0 — Malignant ascites
Is R18.0 billable?
Yes — R18.0 is billable for FY2027. R18.0 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. R18.0 may be submitted for encounters from October 1, 2026 through September 30, 2027.
R18.0 at a glance
| Code | R18.0 |
|---|---|
| Description | Malignant ascites |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to R18.0?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name R18.0 directly.
CMS will reject this code as the principal diagnosis on an inpatient claim. It describes something other than the condition chiefly responsible for the admission.
Which MS-DRGs does R18.0 group to?
R18.0 sits in MDC 23 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 947Signs and Symptoms with MCCmedical
- 948Signs and Symptoms without MCCmedical
As a secondary diagnosis, R18.0 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is R18.0 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to R18.0. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Ascites › malignant (abdominal)
Code first
The underlying condition below must be sequenced before R18.0. R18.0 describes a manifestation and cannot be the principal or first-listed diagnosis.
Excludes1 — never code together — inherited from R18
The conditions below can never be reported together with R18.0 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from Chapter 18
The conditions below are not part of R18.0, but a patient may have both at the same time. When documentation supports it, R18.0 and the excluded code may both be reported.
Excludes2 — not included here — inherited from R10-R19
The conditions below are not part of R18.0, but a patient may have both at the same time. When documentation supports it, R18.0 and the excluded code may both be reported.
- 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)
How long has R18.0 existed?
R18.0 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.