What is ICD-10 code E08.621?

E08.621 is the ICD-10-CM diagnosis code for Diabetes mellitus due to underlying condition with foot ulcer. Diabetes caused by another medical condition that leads to an open sore or ulcer on the foot. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E08.621 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E08.621 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. E08.621 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. E08.621 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

2026 ICD-10-CM E08.621: Diabetes mellitus due

E08.621 maps to CMS-HCC V28 HCCs 37 and 383. Source-labeled RAF references are available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupE08.621

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Diabetes mellitus (E08-E13)

E08.621

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Diabetes mellitus due to underlying condition with foot ulcer

Diabetes caused by another medical condition that leads to an open sore or ulcer on the foot.

Buddy Insight

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 37

Diabetes with Chronic Complic...

Code-level coefficient reference

+ HCC 383

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 020

HHS-HCC 020 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 18

Diabetes with Chronic Complic...

Code-level coefficient reference

+ HCC 161

RXHCC

Mapped

HCC 30

Diabetes with Complications

Code-level coefficient reference

+ HCC 311

Code Book Path

Official

E08.6Diabetes mellitus due to underlying condition with other specified complications E08.62Diabetes mellitus due to underlying condition with skin complications E08.621Diabetes mellitus due to underlying condition with foot ulcer

Inclusion Terms

Official

No inclusion terms are included in this display for E08.621. Check the code and parent instructions in the Code Book.

Excludes 2

Official

No Excludes 2 notes are included in this display for E08.621. Check the code and parent instructions in the Code Book.

Related Codes

Official

E08.620Diabetes mellitus due to underlying condition with diabetic dermatitis E08.622Diabetes mellitus due to underlying condition with other skin ulcer E08.628Diabetes mellitus due to underlying condition with other skin complications

Includes

Official

No Includes notes are included in this display for E08.621. Check the code and parent instructions in the Code Book.

Excludes 1

Official

transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E08
drug or chemical induced diabetes mellitus (E09.-)Inherited from E00-E89, E08
gestational diabetes (O24.4-)Inherited from E00-E89, E08
neonatal diabetes mellitus (P70.2)Inherited from E00-E89, E08
postpancreatectomy diabetes mellitus (E13.-)Inherited from E00-E89, E08
postprocedural diabetes mellitus (E13.-)Inherited from E00-E89, E08
secondary diabetes mellitus NEC (E13.-)Inherited from E00-E89, E08
type 1 diabetes mellitus (E10.-)Inherited from E00-E89, E08
type 2 diabetes mellitus (E11.-)Inherited from E00-E89, E08

Code First

Official

the underlying condition, such as:Inherited from E08
congenital rubella (P35.0)Inherited from E08
Cushing's syndrome (E24.-)Inherited from E08
cystic fibrosis (E84.-)Inherited from E08
malignant neoplasm (C00-C96)Inherited from E08
malnutrition (E40-E46)Inherited from E08
pancreatitis and other diseases of the pancreas (K85-K86.-)Inherited from E08

Use Additional

Official

code to identify site of ulcer (L97.4-, L97.5-)
code to identify control using:Inherited from E08
injectable non-insulin antidiabetic drugs (Z79.85)Inherited from E08
insulin (Z79.4)Inherited from E08
oral antidiabetic drugs (Z79.84)Inherited from E08
oral hypoglycemic drugs (Z79.84)Inherited from E08

Code Also

Official

No Code Also instructions are included in this display for E08.621. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Document the underlying condition causing diabetes, the foot ulcer location (plantar, dorsal, heel, toe), size and depth (Wagner or University of Texas classification), presence of infection, peripheral vascular status, and neuropathy assessment.

Use additional codes for laterality (L97.x) and specify the severity/depth of the ulcer.

Record offloading strategy and wound care plan.

MEAT Support

HCC Buddy guidance

Use additional codes for laterality (L97.x) and specify the severity/depth of the ulcer.

Record offloading strategy and wound care plan.

Audit Caution

HCC Buddy guidance

This code requires an additional L97.x code to specify the exact location, laterality, and severity of the foot ulcer.

Do not use this code for pressure ulcers, which are coded separately under L89.x.

If osteomyelitis underlies the ulcer, it must be coded separately.

Ensure the wound care plan and offloading are documented to support medical necessity.

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is E08.621 an HCC code?

Yes. E08.621 (Diabetes mellitus due to underlying condition with foot ulcer) maps to HCC 37, Diabetes with Chronic Complications and HCC 383, Chronic Ulcer of Skin, Except Pressure, Not Specified as Through to Bone or Muscle under the CMS-HCC V28 risk adjustment model, with source-labeled community non-dual aged reference coefficients HCC 37 0.166 and HCC 383 0.646. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: E08.621 is billable and maps to V28 HCC 37, Diabetes with Chronic Complications and HCC 383, Chronic Ulcer of Skin, Except Pressure, Not Specified as Through to Bone or Muscle. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: E08.621
Description: Diabetes mellitus due to underlying condition with foot ulcer
HCC (V28): HCC 37 — Diabetes with Chronic Complications; HCC 383 — Chronic Ulcer of Skin, Except Pressure, Not Specified as Through to Bone or Muscle
RAF reference coefficient: HCC 37: 0.166; HCC 383: 0.646
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 37, Diabetes with Chronic Complications

0.166

+ HCC 383, Chronic Ulcer of Skin, Except Pressure, Not Specified as Through to Bone or Muscle0.646

ESRDHCC 18, Diabetes with Chronic Complications

Not separately weighted

+ HCC 161, Chronic Ulcer of Skin/Except PressureNot separately weighted

RxHCCHCC 30, Diabetes with Complications

Not separately weighted

+ HCC 311, Chronic Ulcer of Skin, Except PressureNot separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work E08.621 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E08.621

For E08.621, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

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What This Code Means

E08.621 is the ICD-10-CM diagnosis code for diabetes mellitus due to underlying condition with foot ulcer. Diabetes caused by another medical condition that leads to an open sore or ulcer on the foot. E08.621 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering diabetes mellitus (e08-e13).

Under the CMS-HCC V28 risk adjustment model, E08.621 maps to Diabetes with Chronic Complications (HCC 37) with a source-labeled community, non-dual, aged reference coefficient of 0.166. No V24 mapping is shown for E08.621; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use additional codes to specify the location, severity, and stage of the foot ulcer. For E08.621, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E08.621 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use additional codes to specify the location, severity, and stage of the foot ulcer
•Document whether the ulcer is infected or has other complications

Clinical Significance

Diabetes mellitus due to an underlying condition with foot ulcer is a major complication resulting from the triad of neuropathy, peripheral vascular disease, and impaired wound healing characteristic of diabetes. Diabetic foot ulcers precede approximately 85% of non-traumatic lower extremity amputations and represent a significant burden on healthcare resources with prolonged healing times averaging 3-6 months. The underlying condition causing the diabetes adds another layer of complexity to wound management.

Documentation Requirements

✓Document the underlying condition causing diabetes, the foot ulcer location (plantar, dorsal, heel, toe), size and depth (Wagner or University of Texas classification), presence of infection, peripheral vascular status, and neuropathy assessment.
✓Use additional codes for laterality (L97.x) and specify the severity/depth of the ulcer.
✓Record offloading strategy and wound care plan.