2026 ICD-10-CM Diagnosis Code E10.21Type 1 diabetes mellitus with diabetic nephropathy
ICD-10-CM Codes›E00–E89›E08-E13›E10
- Billable — Valid for Submission
- Risk Adjusts — HCC 37
- Chronic Condition
E10.21 is a billable ICD-10-CM diagnosis code for type 1 diabetes mellitus with diabetic nephropathy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 8, 10, 19, 673 through 675, 698 through 700. Coders also document this condition as nephrotic syndrome due to diabetes mellitus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Diabetes mellitus with complication; Diabetes mellitus, Type 1; and Nephritis; nephrosis; renal sclerosis.
For Medicare Advantage risk adjustment, E10.21 maps to CMS-HCC Category 37 (Diabetes with Chronic Complications) under the V28 model, adding a risk factor of about 0.166 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Quality Payment Program MeasuresBilling
Medicare quality measures that can apply when E10.21 is part of the patient record.
Diabetes: Hemoglobin A1c (HbA1c) Poor Control (>9%)
High Priority: YES
Measure Type: Intermediateoutcome
Submission Methods: Claims, Electronic Health Record, Cms Web Interface, Registry
Description: Percentage of patients 18-75 years of age with diabetes who had hemoglobin A1c > 9.0% during the measurement period.
Medicare Risk Adjustment (HCC)Billing
E10.21 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Nephrotic syndrome due to diabetes mellitus
- Nephrotic syndrome due to type 1 diabetes mellitus
- Proteinuria due to type 1 diabetes mellitus
- Renal disorder due to type 1 diabetes mellitus
- Serum albumin below reference range
Coding GuidelinesGuidance
The diabetes mellitus codes are combination codes that include the type of diabetes mellitus, the body system affected, and the complications affecting that body system. As many codes within a particular category as are necessary to describe all of the complications of the disease may be used. They should be sequenced based on the reason for a particular encounter. Assign as many codes from categories E08 - E13 as needed to identify all of the associated conditions that the patient has.
The age of a patient is not the sole determining factor, though most type 1 diabetics develop the condition before reaching puberty. For this reason type 1 diabetes mellitus is also referred to as juvenile diabetes.
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Type 1 diabetes mellitus with intercapillary glomerulosclerosis
- Type 1 diabetes mellitus with intracapillary glomerulonephrosis
- Type 1 diabetes mellitus with Kimmelstiel-Wilson disease
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Diabetes Type 1
Diabetes means your blood glucose, or blood sugar, levels are too high. With type 1 diabetes, your pancreas does not make insulin. Insulin is a hormone that helps glucose get into your cells to give them energy. Without insulin, too much glucose stays in your blood.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert E10.21 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About E10.21Overview
What is the ICD-10 code for type 1 diabetes mellitus with diabetic nephropathy?
The ICD-10-CM code for type 1 diabetes mellitus with diabetic nephropathy is E10.21 (sometimes written as E1021). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is E10.21 (Type 1 diabetes mellitus with kidney complications) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report type 1 diabetes mellitus with diabetic nephropathy on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does E10.21 group to?
When type 1 diabetes mellitus with diabetic nephropathy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 8, 10, 19, 673, 674, 675, 698, 699, 700, with relative weights from 0.6899 to 6.6272 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of E10.21?
Under the General Equivalence Mappings, type 1 diabetes mellitus with diabetic nephropathy converts to ICD-9-CM 250.41 (DMI renl nt st uncntrld). The mapping is approximate, so confirm the match fits the documentation.
What HCC is E10.21?
E10.21 (type 1 diabetes mellitus with diabetic nephropathy) maps to CMS-HCC Category 37 (Diabetes with Chronic Complications), commonly written as HCC 37, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 18 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 30.
Does E10.21 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, E10.21 adds a risk adjustment factor of about 0.166 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.166 to 0.280 depending on the payment segment). A more severe related category (HCC 35 and HCC 36) supersedes it when both are reported. See the full factor table on the HCC 37 category page.
