What is ICD-10 code E88.41?

E88.41 is the ICD-10-CM diagnosis code for MELAS syndrome. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E88.41 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E88.41 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. E88.41 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. E88.41 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.

Which HCC does E88.41 map to under V28?

E88.41 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for E88.41?

E88.41 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for E88.41?

E88.41 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports E88.41?

MELAS is an acronym for Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes; document the specific manifestations present (seizures, strokes, encephalopathy) as additional codes to capture the full clinical picture This is a mitochondrial disorder code; verify documentation clearly states MELAS syndrome diagnosis and consider linking to related codes for seizures (G40.-), stroke-like episodes (I63.-), or encephalopathy (G93.4-) as applicable E88.41 is not a CMS-HCC V28 payment code in the verified current source, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

Can E88.41 be a primary diagnosis?

Yes. E88.41 carries no code-first instruction in the FY2026 tabular, so it can be the first-listed diagnosis when it is the condition chiefly responsible for the encounter and the note supports it, and it can also be reported as a secondary diagnosis. For risk adjustment the order does not matter; the V28 category is the same either way.

Which codes cannot be reported with E88.41?

The Excludes1 note that applies to E88.41 lists transitory endocrine and metabolic disorders specific to newborn (P70-P74); androgen insensitivity syndrome (E34.5-); congenital adrenal hyperplasia (E25.0); hemolytic anemias attributable to enzyme disorders (D55.-); and 9 more (see the notes on this page). An Excludes1 condition is not reported together with E88.41; report one or the other, unless the two conditions are unrelated, which the ICD-10-CM Official Guidelines (Section I.A.12.a) allow. The Excludes2 note lists Ehlers-Danlos syndromes (Q79.6-); those are separate conditions that may be reported together with E88.41 when both are documented.

2026 ICD-10-CM E88.41: MELAS syndrome

E88.41 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupE88.41

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)

E88.41

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

MELAS syndrome

MELAS syndrome is a rare inherited neurological disorder characterized by stroke-like episodes, seizures, and progressive brain dysfunction that typically begins in childhood. The condition affects the mitochondria (the energy-producing parts of cells), leading to inadequate oxygen supply to the brain and muscles.

Buddy Insight

MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes) syndrome is a specific mitochondrial disorder characterized by recurrent stroke-like episodes, seizures, lactic acidosis, and progressive neurological decline.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

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

Context needed

HCC 028

Conditional HHS-HCC mapping: HCC 028 when age < 21. Select the member context before showing a coefficient reference. Metal level and model segment are required for coefficients; no single RAF is shown.

Coefficient needs member context

ESRD/PACE

Context needed

HCC 23

ESRD candidates: HCC 23 when age < 21 or age >= 21. ESRD mapping is separate from PACE. Dialysis, graft, age, and other member context determine the applicable coefficient.

Coefficient needs member context

RXHCC

Mapped

HCC 43

Pituitary, Adrenal Gland, and...

Code-level coefficient reference

Code Book Path

Official

E88Other and unspecified metabolic disorders E88.4Mitochondrial metabolism disorders E88.41MELAS syndrome

Inclusion Terms

Official

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes

Excludes 2

Official

Ehlers-Danlos syndromes (Q79.6-)Inherited from E70-E88

Related Codes

Official

E88.40Mitochondrial metabolism disorder, unspecified E88.42MERRF syndrome E88.43Disorders of mitochondrial tRNA synthetases E88.49Other mitochondrial metabolism disorders

Includes

Official

No Includes notes are included in this display for E88.41. 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, E70-E88, E88, E88.4
androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88, E88, E88.4
congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88, E88, E88.4
hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88, E88, E88.4
Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88, E88, E88.4
5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88, E88, E88.4
histiocytosis X (chronic) (C96.6)Inherited from E00-E89, E70-E88, E88, E88.4
disorders of pyruvate metabolism (E74.4)Inherited from E00-E89, E70-E88, E88, E88.4
Kearns-Sayre syndrome (H49.81)Inherited from E00-E89, E70-E88, E88, E88.4
Leber's disease (H47.22)Inherited from E00-E89, E70-E88, E88, E88.4
Leigh's encephalopathy (G31.82)Inherited from E00-E89, E70-E88, E88, E88.4
Mitochondrial myopathy, NEC (G71.3)Inherited from E00-E89, E70-E88, E88, E88.4
Reye's syndrome (G93.7)Inherited from E00-E89, E70-E88, E88, E88.4

Code First

Official

No Code First sequencing instructions are included in this display for E88.41. Check the code and parent instructions in the Code Book.

Use Additional

Official

codes for associated conditionsInherited from E88

Code Also

Official

No Code Also instructions are included in this display for E88.41. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Confirmed MELAS diagnosis (clinical criteria plus genetic testing for mitochondrial DNA mutation, typically m.3243A>G)

Documentation of characteristic features (stroke-like episodes, seizures, lactic acidosis, myopathy)

Genetic testing results showing mitochondrial DNA mutation

Current neurological status and cognitive assessment

MEAT Support

HCC Buddy guidance

Confirmed MELAS diagnosis (clinical criteria plus genetic testing for mitochondrial DNA mutation, typically m.3243A>G)

Documentation of characteristic features (stroke-like episodes, seizures, lactic acidosis, myopathy)

Genetic testing results showing mitochondrial DNA mutation

Current neurological status and cognitive assessment

Audit Caution

HCC Buddy guidance

Coding stroke-like episodes as actual cerebral infarctions — MELAS episodes have a different mechanism

Using the unspecified mitochondrial code (E88.40) when MELAS is specifically diagnosed

Not coding associated manifestations separately when they require independent management

Confusing MELAS with MERRF — different syndromes with different genetic mutations

Common Mistakes

HCC Buddy guidance

E88.42 — MERRF syndrome: different mitochondrial syndrome with myoclonus epilepsy as primary feature

E88.40 — Mitochondrial metabolism disorder, unspecified: less specific; use E88.41 when MELAS is confirmed

I63.9 — Cerebral infarction, unspecified: MELAS stroke-like episodes are NOT true ischemic strokes

G40.909 — Epilepsy, unspecified: seizures in MELAS are part of the syndrome, not a separate epilepsy diagnosis

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 E88.41 an HCC code?

E88.41 is not in the CMS-HCC V28 or V24 community payment model. E88.41 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E88.41 also appears in the HHS-HCC commercial risk model (HCC 028 (HHS-HCC 028 child, RAF varies by metal level)), where the result depends on member context and is not a Medicare Advantage payment mapping.

Code: E88.41
Description: MELAS syndrome
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

RxHCCHCC 43, Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders

Not 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 E88.41 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E88.41

For E88.41, 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

E88.41 is the ICD-10-CM diagnosis code for melas syndrome. MELAS syndrome is a rare inherited neurological disorder characterized by stroke-like episodes, seizures, and progressive brain dysfunction that typically begins in childhood. The condition affects the mitochondria (the energy-producing parts of cells), leading to inadequate oxygen supply to the brain and muscles. E88.41 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

E88.41 has no mapping under the CMS-HCC V28 or V24 community payment models. E88.41 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E88.41 also appears in the HHS-HCC commercial risk model (HCC 028 (HHS-HCC 028 child, RAF varies by metal level)), where the result depends on member context and is not a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.

MELAS is an acronym for Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes; document the specific manifestations present (seizures, strokes, encephalopathy) as additional codes to capture the full clinical picture.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E88.41 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•MELAS is an acronym for Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes; document the specific manifestations present (seizures, strokes, encephalopathy) as additional codes to capture the full clinical picture
•This is a mitochondrial disorder code; verify documentation clearly states MELAS syndrome diagnosis and consider linking to related codes for seizures (G40.-), stroke-like episodes (I63.-), or encephalopathy (G93.4-) as applicable

Clinical Significance

Documentation Requirements

✓Confirmed MELAS diagnosis (clinical criteria plus genetic testing for mitochondrial DNA mutation, typically m.3243A>G)
✓Documentation of characteristic features (stroke-like episodes, seizures, lactic acidosis, myopathy)
✓Genetic testing results showing mitochondrial DNA mutation
✓Current neurological status and cognitive assessment
✓Serum and CSF lactate levels
✓Multi-system assessment (cardiac, endocrine, auditory, ophthalmologic)
✓Treatment plan (seizure management, metabolic support, coenzyme Q10, L-arginine)

Commonly Confused Codes

•E88.42: MERRF syndrome: different mitochondrial syndrome with myoclonus epilepsy as primary feature
•E88.40: Mitochondrial metabolism disorder, unspecified: less specific; use E88.41 when MELAS is confirmed
•I63.9: Cerebral infarction, unspecified: MELAS stroke-like episodes are NOT true ischemic strokes
•G40.909: Epilepsy, unspecified: seizures in MELAS are part of the syndrome, not a separate epilepsy diagnosis

Child Codes

E88.40Mitochondrial metabolism disorder, unspecified

E88.41MELAS syndrome

E88.42MERRF syndrome

E88.43Disorders of mitochondrial tRNA synthetases

E88.49Other mitochondrial metabolism disorders

Code Hierarchy

└E88Other and unspecified metabolic disorders └E88.4Mitochondrial metabolism disorders └E88.41MELAS syndrome

└E88.41MELAS syndrome

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E88.41

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HCC Category Mapping

MEAT review for E88.41

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Child Codes

Code Hierarchy

Also searched as

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E88.41 ICD-10-CM Code: MELAS syndrome

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E88.41

Is E88.41 an HCC code?

HCC Category Mapping

MEAT review for E88.41

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Child Codes

Code Hierarchy

Also searched as

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