a. Chronic kidney disease
1) Stages of chronic kidney disease (CKD)
The ICD-10-CM classifies CKD based on severity. The severity of CKD is designated by stages 1-5. Stage 2, code N18.2, equates to mild CKD; stage 3, code N18.3, equates to moderate CKD; and stage 4, code N18.4, equates to severe CKD. Code N18.6, End stage renal disease (ESRD), is assigned when the provider has documented end-stage-renal disease (ESRD). If both a stage of CKD and ESRD are documented, assign code N18.6 only.
2) Chronic kidney disease and kidney transplant status
Patients who have undergone kidney transplant may still have some form of chronic kidney disease (CKD) because the kidney transplant may not fully restore kidney function. Therefore, the presence of CKD alone does not constitute a transplant complication. Assign the appropriate N18 code for the patient's stage of CKD and code Z94.0, Kidney transplant status. If a transplant complication such as failure or rejection or other transplant complication is documented, see section I.C.19.g for information on coding complications of a kidney transplant. If the documentation is unclear as to whether the patient has a complication of the transplant, query the provider.
3) Chronic kidney disease with other conditions
Patients with CKD may also suffer from other serious conditions, most commonly diabetes mellitus and hypertension. The sequencing of the CKD code in relationship to codes for other contributing conditions is based on the conventions in the Tabular List. See I.C.9. Hypertensive chronic kidney disease. See I.C.19. Chronic kidney disease and kidney transplant complications.