ICD-10 Code E10.21 – Type 1 diabetes mellitus with diabetic nephropathy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E10.21 – Type 1 diabetes mellitus with diabetic nephropathy
What it is
E10.21 identifies type 1 diabetes mellitus complicated by diabetic nephropathy. Use it when the record links type 1 diabetes to kidney damage caused by diabetes.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include diabetic kidney disease, persistent proteinuria, declining renal function, or nephrology assessment noting diabetic nephropathy.
When to use this code
Use this code when the provider documents type 1 diabetes with diabetic nephropathy, diabetic renal disease, or kidney damage due to diabetes. The diagnosis should clearly connect the nephropathy to diabetes. If the record only says chronic kidney disease, check documentation before assigning this code.
Do not use for
Do not use E10.21 for type 2 diabetes or for kidney disease not documented as diabetic nephropathy. Do not assume nephropathy from abnormal renal tests alone; check documentation.
Coding tip
Assign E10.21 only when the provider explicitly documents the diabetic link between type 1 diabetes and nephropathy.