R18Ascites

R18 is the ICD-10-CM diagnosis code for ascites. It belongs to block R10-R19 (symptoms and signs involving the digestive system and abdomen) and chapter 18 (symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: R18.0 (ascites) and R18.8 (ascites).

Don't report R18 together with the conditions in its Excludes1 note: ascites in alcoholic cirrhosis (K70.31), ascites in alcoholic hepatitis (K70.11) and ascites in toxic liver disease with chronic active hepatitis (K71.51).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.