| N18 | Chronic kidney disease (CKD) | NON-BILLABLE CODE |
| N18.1 | Chronic kidney disease, stage 1 | BILLABLE CODE |
| N18.2 | Chronic kidney disease, stage 2 (mild) | BILLABLE CODE |
| N18.3 | Chronic kidney disease, stage 3 (moderate) | NON-BILLABLE CODE |
| N18.30 | Chronic kidney disease, stage 3 unspecified | BILLABLE CODE |
| N18.31 | Chronic kidney disease, stage 3a | BILLABLE CODE |
| N18.32 | Chronic kidney disease, stage 3b | BILLABLE CODE |
| N18.4 | Chronic kidney disease, stage 4 (severe) | BILLABLE CODE |
| N18.5 | Chronic kidney disease, stage 5 | BILLABLE CODE |
| N18.6 | End stage renal disease | BILLABLE CODE |
