K59.0Constipation

K59.0 is the ICD-10-CM diagnosis code for constipation. It belongs to category K59 (other functional intestinal disorders), 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 6 subcodes must be used instead.

Within K59 (other functional intestinal disorders), K59.0 is specifically for constipation. Related codes cover functional diarrhea (K59.1), neurogenic bowel, not elsewhere classified (K59.2), megacolon, not elsewhere classified (K59.3), anal spasm (K59.4), other specified functional intestinal disorders (K59.8) and functional intestinal disorder, unspecified (K59.9).

To report this condition, pick the subcode that matches the documentation: K59.00 (unspecified), K59.01 (constipation), K59.02 (constipation), K59.03 (constipation), K59.04 (constipation) and K59.09 (constipation).

Don't report K59.0 together with the conditions in its Excludes1 note: fecal impaction (K56.41).

The conditions in its Excludes2 note aren't part of K59.0, but may be coded alongside it if the patient has both: incomplete defecation (R15.0).

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