| K59 | Other functional intestinal disorders | NON-BILLABLE CODE |
| K59.0 | Constipation | NON-BILLABLE CODE |
| K59.00 | Constipation, unspecified | BILLABLE CODE |
| K59.01 | Slow transit constipation | BILLABLE CODE |
| K59.02 | Outlet dysfunction constipation | BILLABLE CODE |
| K59.03 | Drug induced constipation | BILLABLE CODE |
| K59.04 | Chronic idiopathic constipation | BILLABLE CODE |
| K59.09 | Other constipation | BILLABLE CODE |
| K59.1 | Functional diarrhea | BILLABLE CODE |
| K59.2 | Neurogenic bowel, not elsewhere classified | BILLABLE CODE |
| K59.3 | Megacolon, not elsewhere classified | NON-BILLABLE CODE |
| K59.31 | Toxic megacolon | BILLABLE CODE |
| K59.39 | Other megacolon | BILLABLE CODE |
| K59.4 | Anal spasm | BILLABLE CODE |
| K59.8 | Other specified functional intestinal disorders | NON-BILLABLE CODE |
| K59.89 | Other specified functional intestinal disorders | BILLABLE CODE |
| K59.9 | Functional intestinal disorder, unspecified | BILLABLE CODE |
