Crystal's MCW Coder Hub⚕️ICD-10 CM E10.3491 - Type 1 Diabetes Mellitus with Severe Nonproliferative Diabetic Retinopathy Without Macular Edema, Right Eye
Full Official Descriptor: ICD-10-CM E10.3491 - Type 1 diabetes mellitus with severe nonproliferative diabetic retinopathy without macular edema, right eye
ICD-10-CM Chapter: Chapter 4 - Endocrine, Nutritional and Metabolic Diseases (E00-E89) Block: E10 - Type 1 Diabetes Mellitus Billable/Specific Code: ✅ Yes — valid and billable for FY 2024-2026 Laterality: Right Eye
🔬 Clinical Overview
Type 1 Diabetes Mellitus (T1DM) is an autoimmune condition characterized by immune-mediated destruction of pancreatic beta cells, resulting in absolute insulin deficiency. It is coded under the E10.- category in ICD-10-CM. Unlike Type 2 diabetes (E11.-), Type 1 DM does not require documentation of insulin use to assign a code from the E10 category — insulin dependence is inherent and assumed.
Diabetic Retinopathy (DR) is the most common microvascular complication of diabetes mellitus and a leading cause of preventable blindness in working-age adults. It results from chronic hyperglycemia causing progressive damage to the retinal microvasculature — including pericyte loss, basement membrane thickening, increased vascular permeability, microaneurysm formation, capillary occlusion, and retinal ischemia.
Stages of Diabetic Retinopathy (ICD-10-CM Classification)
| Stage | ICD-10 Digit (5th) | Key Findings |
|---|---|---|
| Mild NPDR | 2 (E10.32x) | Microaneurysms only |
| Moderate NPDR | 3 (E10.33x) | Microaneurysms + dot/blot hemorrhages, hard exudates, cotton wool spots |
| Severe NPDR | 4 (E10.34x) | Any one of the “4-2-1 Rule” criteria (see below) |
| Proliferative DR (PDR) | 5 (E10.35x) | Neovascularization of disc (NVD) or elsewhere (NVE), vitreous hemorrhage, TRD |
⚡ The 4-2-1 Rule for Severe NPDR (ETDRS Criteria)
Severe NPDR is defined clinically by the 4-2-1 Rule — the presence of any ONE of the following:
- 4 Quadrants — Intraretinal hemorrhages (>20 per quadrant) in all 4 retinal quadrants
- 2 Quadrants — Venous beading in 2 or more quadrants
- 1 Quadrant — Intraretinal microvascular abnormalities (IRMA) in at least 1 quadrant
📌 Clinical Significance of Severe NPDR: Approximately 50% of eyes with severe NPDR will progress to Proliferative DR within 1 year without treatment, making early identification and close monitoring critical. The absence of macular edema (as in E10.3491) means DME (diabetic macular edema) has not yet developed in the right eye, which is a clinically important distinction for treatment planning.
📋 Code Details
| Field | Detail |
|---|---|
| ICD-10-CM Code | E10.3491 |
| Full Descriptor | Type 1 diabetes mellitus with severe nonproliferative diabetic retinopathy without macular edema, right eye |
| Chapter | Chapter 4 - Endocrine, Nutritional and Metabolic Diseases |
| Block | E10 - Type 1 Diabetes Mellitus |
| Parent Code | E10.34 (non-billable; requires additional character) |
| Billable | ✅ Yes |
| Laterality Specified | Right Eye (7th character = 1) |
| Macular Edema Present? | ❌ No — “without macular edema” |
| Code Type | Diagnosis code — pairs with procedure (CPT) codes |
| wRVU | N/A — this is a diagnosis code; wRVU applies to associated CPT procedure codes |
| Assistant Payable | N/A — diagnosis code; see associated CPT codes |
| Valid FY | FY2024 - FY2026 (confirmed current) |
| POA Indicator Required | ✅ Yes — for inpatient claims; E10.3491 is reportable as POA (Present on Admission) |
⚠️ Important Coding Note: E10.3491 is a combination code — it captures both the Type 1 diabetes AND the specific retinal complication in a single code. Per ICD-10-CM Official Guidelines Section I.C.4.a.2, you should not separately code the retinopathy as a standalone ophthalmic diagnosis (e.g., H36) when using a diabetic combination code from the E10.- category. The diabetes chapter code is sequenced first.
✅ Includes / Use Additional Code Instructions
Included in E10.3491
- Type 1 (insulin-dependent) diabetes mellitus (brittle diabetes, diabetes due to autoimmune process, diabetes due to immune-mediated pancreatic islet beta-cell destruction, idiopathic diabetes, juvenile-onset diabetes, ketosis-prone diabetes)
- Severe nonproliferative diabetic retinopathy stage
- Right eye laterality
- Absence of macular edema in the right eye
Use Additional Code Instructions (Mandatory or Instructional Notes)
Per ICD-10-CM tabular instructions for E10.-, use additional codes when applicable:
| Additional Code | Description | When to Apply |
|---|---|---|
| Z79.4 | Long-term (current) use of insulin | Almost always applicable in T1DM — apply routinely |
| Z79.85 | Long-term (current) use of injectable non-insulin antidiabetic drugs | If patient uses GLP-1 agonist or similar injectable alongside insulin |
| Z79.84 | Long-term (current) use of oral antidiabetic drugs | If patient is also using oral agents (less common in T1DM but possible) |
| H35.81 | Retinal edema | Only if retinal edema is separately documented and distinct from DME |
| Z83.3 | Family history of diabetes mellitus | Optional; useful for preventive care coding |
📌 Z79.4 Coding Tip: For all Type 1 diabetes patients, Z79.4 should be assigned as a matter of routine, even if insulin is not explicitly re-documented at every visit. T1DM patients are permanently insulin-dependent; absence of insulin mention does not negate the code. Document once clearly and maintain in the problem list.
🚫 Excludes
Excludes 1 (Cannot be coded together — mutually exclusive)
| Code(s) | Description |
|---|---|
| E08.- | Diabetes mellitus due to underlying condition |
| E09.- | Drug or chemical induced diabetes mellitus |
| O24.4- | Gestational diabetes mellitus |
| P70.2 | Neonatal diabetes mellitus |
| E13.- | Other specified diabetes mellitus (post-pancreatectomy, postprocedural, secondary NEC) |
| E11.- | Type 2 diabetes mellitus |
⚠️ Critical Distinction: Do not assign E10.3491 if the patient has Type 2 DM — use E11.3491 instead. Do not assign E10.- for secondary diabetes (use E08.-, E09.-, or E13.- as appropriate). Type 1 DM is specifically reserved for autoimmune or idiopathic absolute insulin deficiency.
Excludes 2 (May be coded together when both conditions are present)
| Code(s) | Description |
|---|---|
| H36 | Retinal disorders in diseases classified elsewhere |
| N18.- | Chronic kidney disease |
🏷️ HCC Risk Adjustment Mapping
This code is an HCC-mapped diagnosis — accurate and complete documentation is critical for appropriate risk adjustment and reimbursement in Medicare Advantage and other value-based care programs.
CMS-HCC Version 24 (V24) — Reference / Historical
| HCC | Category Name | RAF Contribution (approx.) |
|---|---|---|
| HCC 18 | Diabetes with Ophthalmologic Manifestations | ~0.200 (Community, Non-Dual, Aged) |
Under V24, diabetic complications carried a higher risk adjustment factor (RAF) than uncomplicated diabetes (HCC 19). The distinction between “with complications” (HCC 17, 18) and “without complications” (HCC 19) was clinically and financially meaningful.
CMS-HCC Version 28 (V28) — Active (Fully Implemented 2026)
| HCC | Category Name | RAF Contribution (approx.) |
|---|---|---|
| HCC 38 | Diabetes with Ophthalmologic or Unspecified Manifestation | ~0.166 (Community, Non-Dual, Aged) |
⚠️ V28 Critical Change: Under CMS-HCC V28 (fully phased in for 2026), all diabetes categories are constrained — meaning the RAF contribution is the same regardless of whether the patient has uncomplicated diabetes or has complications like diabetic retinopathy. Under V24, diabetic retinopathy (HCC 18) contributed a meaningfully higher RAF than uncomplicated DM (HCC 19). Under V28, this advantage is eliminated — HCC 38 carries the same coefficient (~0.166) as uncomplicated diabetes (HCC 35). This is a significant change for ophthalmology and endocrinology risk adjustment revenue.
💡 Why This Still Matters: Even though the RAF differential between “complicated” and “uncomplicated” diabetes is gone in V28, accurately coding E10.3491 still:
- Documents the true clinical complexity of the patient
- Supports quality measure performance (e.g., MIPS Measure #117 - Diabetes: Eye Exam)
- Establishes medical necessity for ophthalmic diagnostic procedures
- Creates an accurate longitudinal problem list for care management
- Protects against undercoding audits in value-based care contracts
🏥 MS-DRG Applicability
MS-DRG: ✅ Applicable for Inpatient Stays
When E10.3491 is reported as the principal diagnosis on an inpatient claim, it maps to the following MS-DRGs depending on the presence of Comorbid Conditions (CC) or Major Comorbid Conditions (MCC):
| MS-DRG | Description | Condition |
|---|---|---|
| 637 | Diabetes with MCC | When a Major Complication/Comorbidity (MCC) is present (e.g., sepsis, acute renal failure) |
| 638 | Diabetes with CC | When a Complication/Comorbidity (CC) is present (e.g., hypertension, CKD Stage 3) |
| 639 | Diabetes without CC/MCC | No qualifying CC or MCC present |
📌 Inpatient Coding Note: E10.3491 alone (severe NPDR without macular edema) is unlikely to be a principal inpatient diagnosis by itself. More commonly, it will appear as a secondary diagnosis alongside an acute complication of diabetes (e.g., DKA — E10.10, hyperosmolarity, or hypoglycemic episode), a vascular event, or a surgical procedure. In that context, it acts as an additional CC that can influence MS-DRG assignment by increasing severity of illness (SOI) and expected length of stay.
⚡ POA (Present on Admission): Must be indicated on UB-04 claims. For a chronic condition like diabetic retinopathy that is pre-existing, POA = Y (Yes) in almost all cases.
🌳 Code Tree
Parent → Sibling → Child Structure for E10.3491
E10 - Type 1 Diabetes Mellitus (non-billable)
│
├── E10.31 - T1DM with unspecified diabetic retinopathy (non-billable header)
│ ├── E10.311 - T1DM with unspecified DR with macular edema
│ └── E10.319 - T1DM with unspecified DR without macular edema
│
├── E10.32 - T1DM with mild nonproliferative DR (NPDR) (non-billable header)
│ ├── E10.3211 - T1DM with mild NPDR with macular edema, right eye
│ ├── E10.3212 - T1DM with mild NPDR with macular edema, left eye
│ ├── E10.3213 - T1DM with mild NPDR with macular edema, bilateral
│ ├── E10.3291 - T1DM with mild NPDR without macular edema, right eye
│ ├── E10.3292 - T1DM with mild NPDR without macular edema, left eye
│ ├── E10.3293 - T1DM with mild NPDR without macular edema, bilateral
│ └── E10.3299 - T1DM with mild NPDR without macular edema, unspecified eye
│
├── E10.33 - T1DM with moderate NPDR (non-billable header)
│ ├── E10.3311 - T1DM with moderate NPDR with macular edema, right eye
│ ├── E10.3312 - T1DM with moderate NPDR with macular edema, left eye
│ ├── E10.3313 - T1DM with moderate NPDR with macular edema, bilateral
│ ├── E10.3391 - T1DM with moderate NPDR without macular edema, right eye
│ ├── E10.3392 - T1DM with moderate NPDR without macular edema, left eye
│ ├── E10.3393 - T1DM with moderate NPDR without macular edema, bilateral
│ └── E10.3399 - T1DM with moderate NPDR without macular edema, unspecified eye
│
├── E10.34 - T1DM with severe NPDR (non-billable header)
│ ├── E10.3411 - T1DM with severe NPDR with macular edema, right eye
│ ├── E10.3412 - T1DM with severe NPDR with macular edema, left eye
│ ├── E10.3413 - T1DM with severe NPDR with macular edema, bilateral
│ ├── E10.3419 - T1DM with severe NPDR with macular edema, unspecified eye
│ ├── E10.3491 - T1DM with severe NPDR without macular edema, right eye ← YOU ARE HERE
│ ├── E10.3492 - T1DM with severe NPDR without macular edema, left eye
│ ├── E10.3493 - T1DM with severe NPDR without macular edema, bilateral
│ └── E10.3499 - T1DM with severe NPDR without macular edema, unspecified eye
│
└── E10.35 - T1DM with proliferative DR (PDR) (non-billable header)
├── E10.3511 - T1DM with PDR with macular edema, right eye
├── E10.3512 - T1DM with PDR with macular edema, left eye
├── E10.3513 - T1DM with PDR with macular edema, bilateral
├── E10.3521 - T1DM with PDR with traction retinal detachment (TRD) involving macula, right eye
├── E10.3522 - T1DM with PDR with TRD involving macula, left eye
├── E10.3531 - T1DM with PDR with TRD not involving macula, right eye
├── E10.3541 - T1DM with PDR with combined TRD and rhegmatogenous RD, right eye
├── E10.3551 - T1DM with stable PDR, right eye
├── E10.3552 - T1DM with stable PDR, left eye
├── E10.3591 - T1DM with PDR without macular edema, right eye
├── E10.3592 - T1DM with PDR without macular edema, left eye
├── E10.3593 - T1DM with PDR without macular edema, bilateral
└── E10.3599 - T1DM with PDR without macular edema, unspecified eye
🔗 Associated CPT Procedure Codes
Since E10.3491 is a diagnosis code, it pairs with relevant CPT procedure codes to form the complete claim. The following CPTs are commonly used in the evaluation and management of severe NPDR:
Diagnostic / Imaging
| CPT Code | Description | wRVU |
|---|---|---|
| 92134 | OCT of retina, unilateral or bilateral (with interpretation and report) | 0.65 |
| 92235 | Fluorescein angiography (FA) with interpretation and report | 1.00 |
| 92250 | Fundus photography with interpretation and report | 0.44 |
| 92240 | ICG angiography with interpretation and report | 1.36 |
| 92242 | FA + ICG at same encounter | ~1.80 |
| 92228 | Remote imaging of retina, low complexity interpretation | 0.42 |
Evaluation and Management
| CPT Code | Description | wRVU |
|---|---|---|
| 99213 | Office visit, established patient, low complexity | 0.97 |
| 99214 | Office visit, established patient, moderate complexity | 1.50 |
| 99215 | Office visit, established patient, high complexity | 2.11 |
| 92004 | Comprehensive ophthalmological exam, new patient | 2.00 |
| 92014 | Comprehensive ophthalmological exam, established patient | 1.34 |
Therapeutic / Procedural (if disease progresses or has associated conditions)
| CPT Code | Description | wRVU |
|---|---|---|
| 67028 | Intravitreal injection of pharmacologic agent (anti-VEGF if DME or CNV develops) | 0.72 |
| 67210 | Photocoagulation, retinal (focal/grid laser for DME if present) | 5.31 |
| 67228 | Photocoagulation, panretinal (PRP laser for severe NPDR / PDR) | 7.29 |
| 67113 | Repair of complex retinal detachment (for advanced PDR with TRD) | 22.97 |
📌 Coding Tip: When billing 92134 (OCT) or 92235 (FA) on the same date as an office visit (99213-99215 or 92014), ensure the diagnostic test has separately documented medical necessity and is not simply bundled into the exam. Modifier -25 on the E/M code may be required to indicate a separately identifiable service on the same day as a procedure.
💡 Coding Examples
Example 1 - Established Patient Ophthalmology Visit (Office, Profee)
A 32-year-old established patient with known Type 1 DM since age 12 presents for diabetic eye exam. Fundoscopic evaluation reveals intraretinal hemorrhages in all 4 quadrants of the right eye and venous beading in 2 quadrants, consistent with severe NPDR. No macular edema is detected on clinical exam or OCT. The left eye shows moderate NPDR. OCT of both retinas is performed and interpreted. Patient is on insulin pump therapy (insulin). Visit is documented at moderate medical complexity level.
Bill:
- 99214--25 (Office visit, established, moderate complexity — modifier -25 since OCT also performed)
- 92134 (OCT of retina, bilateral — unilateral or bilateral; bill once)
- E10.3491 (T1DM with severe NPDR without macular edema, right eye — principal dx)
- E10.3392 (T1DM with moderate NPDR without macular edema, left eye — secondary dx)
- Z79.4 (Long-term use of insulin)
Example 2 - New Patient Comprehensive Exam with FA (Retina Practice)
A 27-year-old new patient with T1DM since childhood is referred by her endocrinologist for retinal evaluation. The retina specialist performs a comprehensive ophthalmological examination and documents findings consistent with severe NPDR right eye (4-2-1 rule met: IRMA present right eye, venous beading right and left) and moderate NPDR left eye. No macular edema right eye; no macular edema left eye. Fluorescein angiography (FA) is performed bilaterally to delineate areas of nonperfusion and assess severity. A formal interpretation and report are completed.
Bill:
- 92004 (Comprehensive ophthalmological exam, new patient)
- 92235 (Fluorescein angiography, bilateral — bill once per unilateral or bilateral descriptor)
- E10.3491 (T1DM with severe NPDR without ME, right eye)
- E10.3392 (T1DM with moderate NPDR without ME, left eye)
- Z79.4 (Long-term insulin use)
📝 Note: 92004 and 92235 can be billed together on the same date when clearly documented as distinct services. No modifier -25 is required when billing 92004 alongside a diagnostic test — -25 applies to E/M codes (992xx), not ophthalmological exam codes (920xx).
Example 3 - Inpatient Coding (Secondary Diagnosis)
A 29-year-old patient with T1DM is admitted for diabetic ketoacidosis (DKA) without coma. Chart documentation also notes pre-existing severe NPDR of the right eye, documented in the problem list and confirmed in the attending physician’s H&P.
Principal Diagnosis:
- E10.10 (T1DM with ketoacidosis without coma)
Secondary Diagnosis:
- E10.3491 (T1DM with severe NPDR without macular edema, right eye)
⚠️ Do NOT code E10.3491 and E10.10 as two separate “diabetes” diagnoses — in ICD-10-CM, when multiple manifestations exist, you report the most specific manifestation codes within the E10 category together. Each specific combination code covers its own complication. Both are valid to report simultaneously as they address different body systems (endocrine vs. ophthalmologic).
POA Indicator: Y (Yes) for E10.3491 — retinopathy was pre-existing MS-DRG Driver: E10.10 drives DKA-related DRG (638 or 639); E10.3491 may serve as a CC modifier to the principal DRG
Example 4 - MIPS Quality Measure Reporting
An ophthalmologist sees a diabetic patient for a dilated eye exam and documents severe NPDR right eye, no macular edema. This encounter qualifies for MIPS Measure #117 (Diabetes: Eye Exam — patients with diabetes who had an eye exam [retinal or dilated] during the measurement period, OR who had a negative exam in the prior year).
Report:
- E10.3491 on the claim supports performance reporting for MIPS Measure #117
- Eligible CPT to trigger the measure: 92004, 92014, 92002, 92012, 99202-99215 with appropriate diagnosis
Tip
📌 Documentation should confirm a dilated fundus exam or retinal imaging was performed. The presence of E10.3491 on an ophthalmology claim with a qualifying CPT code qualifies the encounter for reporting.
Example 5 - Unspecified Eye Code Avoided (Specificity Best Practice)
A coder receives a chart noting “Type 1 diabetic patient with severe NPDR, no macular edema” — no eye laterality documented by provider.
Incorrect:
- E10.3499 — Only use if the provider truly cannot determine laterality
Correct Action:
- Query the provider for laterality — right eye, left eye, or bilateral?
- Assign E10.3491 (right), E10.3492 (left), or E10.3493 (bilateral) based on provider response
Attention
⚠️ Coding Guideline (ICD-10-CM Section I.B.13): When laterality is not documented and it is a condition with a laterality option, query the provider. Do not default to “unspecified” when clinically determinable. Specificity of laterality impacts quality scoring, risk adjustment accuracy, and clinical record integrity.
📎 Documentation Requirements
For E10.3491 to be accurately reported and audit-proof, the medical record must include:
- Explicit diagnosis of Type 1 Diabetes Mellitus — documented by the treating provider (endocrinologist, internist, ophthalmologist); “juvenile-onset,” “brittle,” “IDDM” are acceptable legacy terms that map to Type 1
- Severity of retinopathy — provider must document “severe nonproliferative diabetic retinopathy” or equivalent terminology; ETDRS/4-2-1 rule findings or clinical description must be present
- Laterality — “right eye” must be explicitly documented; avoid “unspecified” when clinical documentation supports a specific eye
- Absence of macular edema — must be documented as “no diabetic macular edema,” “without DME,” or equivalent; if macular edema IS present, use E10.3411 instead
- Causal relationship — physician must link the retinopathy to the diabetes (“diabetic retinopathy” or “retinopathy due to type 1 DM” or “diabetic eye disease”); do not assume causality if not documented
- Insulin use — confirm and document to support Z79.4
- Dilated fundus exam findings — ideally supported by OCT, fundus photography, or FA imaging to substantiate the severity level
⚠️ Audit Vulnerability: One of the most common HCC audit findings in ophthalmology and endocrinology is undercoding diabetic retinopathy severity — e.g., defaulting to “unspecified retinopathy” (E10.31X) when the clinical documentation clearly supports a specific stage such as severe NPDR. Coders should query for specificity rather than accepting vague documentation.
🔁 Payer and Compliance Considerations
- Medicare Advantage (HCC Risk Adjustment): E10.3491 maps to HCC 38 under V28 (fully active 2026) — must be submitted at least once per calendar year to maintain risk adjustment credit; ensure it appears on at least one MA-eligible encounter annually
- MIPS/Quality Reporting: Triggers eligibility for MIPS Measure #117 (Diabetes Eye Exam); important for MIPS performance in ophthalmology and endocrinology practices
- HCC Recapture Programs: Risk adjustment audits commonly target diabetes retinopathy codes — ensure annual documentation and code submission; do not omit from claims if clearly part of the active problem list
- Coding Sequencing: Per ICD-10-CM Official Guidelines Section I.C.4, the diabetes code is always sequenced first (before any ophthalmic complication code); do not sequence a retinal code (H-chapter) as principal when diabetes is the underlying etiology
- V28 Constraining — Practice Implications: Since all diabetes HCCs now carry the same RAF in V28, practices should focus on documenting all active comorbidities (hypertension, CKD, neuropathy, PAD) to maximize total composite risk score — the total patient risk burden now matters more than any single complication
- ICD-10-CM FY Updates: Verify annually in October (new FY start) that E10.3491 remains unchanged; diabetic retinopathy codes are generally stable but check the CMS ICD-10-CM tabular update tables each year
A few critical profee notes 🎯:
The E10.3591 vs. E10.3551 active/stable distinction is one of the highest audit-risk code pairs in retina — physicians need to explicitly state “stable PDR” post-PRP for you to flip the code, and many don’t without prompting.
The vitreous hemorrhage add-on code H43.11 is a commonly missed secondary diagnosis in PDR encounters — the combination code doesn’t capture VH; it needs its own line.
The 010-day global + billing at 150% for bilateral is another frequent billing error in retina practices — only the first session within 10 days is billable per eye, and bilateral gets 150% not 200%.
The bilateral staging rule (code each eye individually when severity differs) is tested frequently on CPC and COC exams and shows up in payer audits — your E10.3591 (right) + E10.3492 (left) example above is a perfect teaching case.
Sources: AAPC Codify E10.3491 · FindACode E10.3491 · ICD10Coded.com E10.3491 · CMS ICD-10-CM/PCS MS-DRG V34 Definitions Manual · CMS ICD-10 Mappings 2026 Risk Adjustment · CMS-HCC V28 Raapid Inc / Wolters Kluwer Analysis · MDaudit HCC Audit 2026 · BCBS AL Common HCC ICD-10 2026 · AAPC Ophthalmology Coding Alert DR Coding · Eyes on Eyecare OD Diabetic Retinopathy Billing Guide · Outsource Strategies International DR Coding · CMS Home Health LCD A56674 Glucose Monitoring ICD-10 Groups · PMC NCBI DR Identification Study 2024 · AMA CPT 2025-2026