ICD-10 Code E11.621: Type 2 Diabetes with Foot Ulcer

Key Takeaways

E11.621 is a billable ICD-10-CM code for Type 2 diabetes mellitus with foot ulcer, valid for FY2026 (October 1, 2025 through September 30, 2026).

An additional L97.4- or L97.5- code is mandatory with E11.621 to identify the ulcer site and laterality – omitting it causes claim denial.

ICD-10-CM guidelines presume a causal link between diabetes and the foot ulcer unless documentation explicitly states otherwise.

Pabau’s claims management software supports accurate ICD-10 code pairing and documentation workflows for wound care and podiatry billing teams.

ICD-10 Code E11.621: Definition and Clinical Description

Diabetic foot ulcers are among the most resource-intensive complications in type 2 diabetes management, affecting roughly 15% of patients over their lifetime according to the Centers for Medicare and Medicaid Services (CMS). Coding them correctly is not a formality – it determines reimbursement, claim approval, and whether the clinical record accurately reflects disease burden. ICD-10 Code E11.621 is the specific ICD-10-CM diagnosis code for Type 2 diabetes mellitus with foot ulcer.

The code sits within Chapter 4 of the ICD-10-CM classification (Endocrine, Nutritional and Metabolic Diseases, E00-E89), under the E11 category for Type 2 diabetes mellitus. It is a billable, specific code – meaning it can be submitted directly on HIPAA-covered transactions without further subdivision. Practices managing diabetic patients can verify the current code status using the CDC/NCHS ICD-10-CM web tool.

The clinical definition covers any foot ulcer that occurs as a complication of Type 2 diabetes. Under ICD-10-CM guidelines, the causal relationship between the diabetes and the ulcer is presumed unless the treating clinician explicitly documents that the two conditions are unrelated. This presumption is significant for coders working in podiatry, wound care, and endocrinology settings.

Inclusion Terms and Synonyms

E11.621 captures several related clinical presentations under a single billable code. Accepted inclusion terms include:

• Diabetic foot ulcer (Type 2)
• Type 2 diabetic ulcer of the foot
• Neuropathic diabetic foot ulcer
• Ischemic diabetic foot ulcer (when not separately classified)
• Chronic foot ulcer due to Type 2 diabetes

These are not separate codes – each maps directly to E11.621 when the underlying condition is Type 2 diabetes mellitus.

Billability and Code Status for FY2026

E11.621 is confirmed as a billable and specific ICD-10-CM code for the current fiscal year. The validity window runs from October 1, 2025 through September 30, 2026 for FY2026 HIPAA-covered transactions. Coders can verify active status via ICD List or the AAPC Codify platform.

The code has been billable continuously since ICD-10-CM implementation and has not been retired or replaced in recent fiscal year updates. For practices using claims management software, E11.621 should appear as an active, selectable diagnosis code in the ICD-10-CM code library without any inactive flags.

Required Additional Code: L97.4- and L97.5-

E11.621 cannot be submitted alone. The ICD-10-CM tabular instructions include a “Use Additional Code” instruction requiring coders to also assign an L97.4- or L97.5- code to identify the specific site of the ulcer. Missing this second code is the most common reason for claim rejection on diabetic foot ulcer encounters.

The L97 category covers non-pressure chronic ulcers of the lower limb, not elsewhere classified. Two subcategories apply to diabetic foot ulcers specifically:

• L97.4- Non-pressure chronic ulcer of heel and midfoot
• L97.5- Non-pressure chronic ulcer of other part of foot (including the ball of the foot and toes)

Both subcategories require a fifth or sixth character to identify laterality (right vs. left) and wound severity. For example, L97.419 captures a non-pressure ulcer of the right heel and midfoot with unspecified severity, while L97.522 captures an ulcer of other part of the left foot with fat layer exposed. Maintaining structured patient records with laterality and wound staging documented at each visit makes this selection straightforward rather than a guessing exercise at the time of billing.

L97 Severity Levels

The final character of the L97 code indicates depth and severity of the wound. Coders must select the highest level of severity documented in the clinical note:

• 1 – Limited to breakdown of skin
• 2 – Fat layer exposed
• 3 – Necrosis of muscle
• 4 – Necrosis of bone
• 9 – Unspecified severity (use only when documentation does not specify)

Wound care teams and podiatrists should document severity explicitly at each encounter. Defaulting to “9” (unspecified) when wound staging information is available in the note is a documentation failure that can trigger Medicare LCD audits. Practices using structured clinical documentation workflows can standardize wound staging capture at the point of care.

ICD-10 Code E11.621 Coding Guidelines and Causal Relationship Rules

ICD-10-CM Section I.C.4.a establishes the governing principle for all diabetic complication coding: when a patient has both diabetes and a condition commonly associated with diabetes, the provider does not need to explicitly state “due to diabetes” in the clinical note. The causal link is presumed. This applies directly to E11.621 – a Type 2 diabetic patient with a foot ulcer is coded with E11.621 unless the documentation says the ulcer is unrelated to the diabetes.

This guideline, maintained by the CMS and NCHS through the ICD-10-CM Official Guidelines for Coding and Reporting, removes the burden of requiring explicit causal language in every note. However, when a physician documents that the ulcer has a different etiology (such as a pressure injury or venous insufficiency), the coder must follow that documentation and not presume a diabetic cause.

Sequencing When Multiple Diabetic Complications Are Present

When a patient presents with multiple diabetic complications in the same encounter, sequencing matters. E11.621 is listed as the principal diagnosis when the foot ulcer is the primary reason for the visit. If the encounter is primarily for diabetes management with the ulcer as a secondary finding, E11.9 (Type 2 diabetes mellitus without complications) or the specific management-related code takes the principal position.

Common combinations requiring careful sequencing:

• E11.621 + E11.51 (peripheral angiopathy without gangrene): sequence based on the primary reason for the visit
• E11.621 + E11.52 (peripheral angiopathy with gangrene): gangrene takes sequencing priority per tabular notes
• E11.621 + Z79.4 (long-term insulin use): always add Z79.4 when the Type 2 patient is on insulin

Practices managing complex diabetic patients benefit from metabolic health EMR systems that support multi-code documentation and sequencing flags within the clinical workflow.

E11.621 vs. E11.622: Understanding the Distinction

Coders frequently confuse E11.621 and E11.622. The distinction is anatomical, not severity-based:

• E11.621 – Type 2 diabetes mellitus with foot ulcer: applies when the ulcer is located on the foot (including the heel, sole, toes, or dorsum)
• E11.622 – Type 2 diabetes mellitus with other skin ulcer: applies when the ulcer is on the lower leg, ankle, or another skin surface that is not the foot

A diabetic ulcer on the shin uses E11.622, not E11.621. An ulcer on the plantar surface of the foot uses E11.621. The corresponding L97 subcategory must match: L97.4- and L97.5- pair with E11.621, while other L97 subcategories pair with E11.622 depending on location. Reviewing the AAPC Codify ICD-10-CM lookup with the laterality and location documented in the clinical note helps confirm the correct pairing before submission.

A second common confusion involves L89 pressure ulcer codes. L89 applies to pressure injuries caused by sustained mechanical pressure – not to diabetic ulcers. L97 codes are specifically for non-pressure chronic ulcers associated with systemic conditions like diabetes. Using an L89 code when the clinical documentation describes a diabetic foot ulcer will cause a payer mismatch and likely a denial. For practices with HIPAA compliance requirements around clinical documentation accuracy, this distinction is an audit risk area worth monitoring.

Accurate ICD-10 Coding Starts with Better Clinical Records

Pabau helps podiatry and wound care teams document wound staging, laterality, and diagnosis codes at the point of care, reducing claim errors and supporting audit-ready records.

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Documentation Requirements for Accurate Code Assignment

Successful E11.621 + L97 code submission depends on documentation quality. Payer audits and Medicare LCD reviews for diabetic foot ulcer encounters consistently flag incomplete clinical notes as the root cause of denials. The clinical note must support every character of both the E11.621 and the companion L97 code.

Required documentation elements for each diabetic foot ulcer encounter:

• Diabetes type confirmed: The note must document Type 2 diabetes mellitus (not just “diabetes” or “DM”)
• Ulcer location: Specific foot location (heel, midfoot, toe, dorsum, plantar surface) to support L97.4- vs L97.5- selection
• Laterality: Right or left foot clearly stated
• Wound depth/severity: Skin breakdown, fat layer exposure, muscle involvement, or bone involvement
• Causal relationship or exclusion: If the clinician believes the ulcer is unrelated to diabetes, this must be explicitly stated
• Insulin use: If the patient uses insulin for their Type 2 diabetes, Z79.4 must also be assigned

Practices using digital intake and clinical forms can build wound assessment templates that capture all required fields systematically, reducing documentation gaps before the claim is even generated. For broader diabetic patient management, weight loss clinic workflows that manage metabolic conditions often overlap with diabetic wound care protocols and face similar documentation demands.

ICD-9-CM Crosswalk and Related Codes

For practices maintaining historical records or working with legacy systems, the approximate ICD-9-CM equivalent of E11.621 is 250.80 (Diabetes with other specified manifestations, Type II or unspecified type, not stated as uncontrolled). The conversion is approximate because ICD-9-CM did not capture wound specificity at the level ICD-10-CM now requires. For reference tools and crosswalk guidance, ResDAC’s ICD codes in Medicare files guide covers the ICD-9 to ICD-10 transition methodology for Medicare claims data.

Coders researching related codes for common comorbidities in diabetic foot ulcer patients can reference these related ICD-10 coding references for associated mental health and comorbidity documentation. For a broader range of ICD-10 code crosswalk guides, the Pabau diagnostic codes library covers multiple specialty areas.

Common Claim Denial Reasons and How to Avoid Them

Diabetic foot ulcer claims consistently rank among the higher denial rates in wound care billing. Most denials trace back to a handful of preventable errors. Podiatry and wound care billing teams using ICD-10 diagnostic coding references for other specialties will find the same root causes appear here: missing required codes, incorrect code pairing, and documentation that does not support the selected code characters.

• Missing L97 code: Submitting E11.621 alone without a companion L97.4- or L97.5- code. This is the single most common denial cause.
• L89 instead of L97: Using pressure ulcer codes for a diabetic ulcer – a classification error that triggers payer mismatch logic.
• Unspecified severity when documented: Selecting L97.XX9 (unspecified) when the clinical note clearly describes wound depth. Auditors flag this as upcoding or documentation failure.
• Missing laterality: L97 codes require right or left specification. A generic laterality-absent L97 code will not pass CMS edits.
• Wrong E11 subcode: Using E11.622 (other skin ulcer) for a foot ulcer, or E11.621 for a shin ulcer.
• Missing Z79.4: Not adding the insulin use code when a Type 2 patient is documented as using insulin.

Pre-claim scrubbing workflows built into HIPAA-compliant medical office systems can flag these pairing errors before submission, reducing the administrative burden of rework on denied claims.

Expert Picks

Need to streamline wound care documentation across your clinic? Digital Forms lets you build structured wound assessment templates that capture laterality, severity, and diagnosis data at the point of care.

Managing diabetic patients across multiple conditions? Metabolic Health EMR supports multi-diagnosis documentation workflows for endocrinology and primary care practices.

Looking to reduce claim errors across your billing workflow? Claims Management Software provides integrated ICD-10 code support and pre-submission validation for podiatry and wound care teams.

Conclusion

Diabetic foot ulcer coding consistently fails at the same point: the required L97 companion code is missing, incomplete, or mismatched. ICD-10 Code E11.621 is straightforward when documentation supports it – but the code pair only works when laterality, ulcer site, and wound severity are captured at every encounter.

Pabau’s digital forms and claims management tools help wound care and podiatry teams standardize that documentation capture, reducing E11.621 denials before they reach the payer. To see how Pabau supports accurate ICD-10 coding workflows in practice, book a demo with the team.

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