R18.0 — Malignant ascites
R18.0 is a billable, specific ICD-10-CM code for malignant ascites. It is valid for submission on a claim.
Risk adjustment
R18.0 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 17 Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic4.209 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.
Medicare coverage
R18.0 is named in 7 Medicare coverage policies — 7 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A56421Billing and Coding: CT of the Abdomen and Pelvis
- A56464Billing and Coding: Flow Cytometry
- A56697Billing and Coding: Non-Invasive Vascular Studies
- A56758Billing and Coding: Non-Invasive Vascular Studies
How R18.0 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to R18.0.
- Ascites›malignant
Related codes at this level
Codes that share R18. If R18.0 is not quite right, the correct code is usually one of these.
Questions about R18.0
- Is R18.0 a billable ICD-10-CM code?
- Yes. R18.0 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does R18.0 sit in the tabular list?
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99), in the block Symptoms and signs involving the digestive system and abdomen (R10-R19).