K59Other functional intestinal disorders

K59 is the ICD-10-CM diagnosis code for other functional intestinal disorders. It belongs to block K55-K64 (other diseases of intestines) and chapter 11 (diseases of the digestive system). It is a header code, so it can't be reported by itself; one of its 7 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: K59.0 (constipation), K59.1 (diarrhea), K59.2 (classified), K59.3 (classified), K59.4 (spasm), K59.8 (disorders) and K59.9 (unspecified).

Don't report K59 together with the conditions in its Excludes1 note: change in bowel habit NOS (R19.4), intestinal malabsorption (K90.-) and psychogenic intestinal disorders (F45.8).

The conditions in its Excludes2 note aren't part of K59, but may be coded alongside it if the patient has both: functional disorders of stomach (K31.-).

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