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E74.03 ICD-10-CM Code: Cori disease

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Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

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

E74.03

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

Cori disease

A rare inherited metabolic disorder where the body cannot properly process glycogen due to debranching enzyme deficiency, causing muscle weakness and liver problems.

Buddy the Bee presenting code insight

Buddy Insight

Cori disease (Glycogen Storage Disease Type III), also known as Forbes disease, is caused by glycogen debranching enzyme deficiency.

CMS-HCC V28

HCC 50

RAF 0.289

CMS-HCC V24

HCC 23

RAF 0.230

ACA/HHS

0

0

RAF 0

ESRD/PACE

HCC 23

RAF 0.0

RXHCC

HCC 43

RAF 0.0

Code Trumping

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Code Book Path

Official
E74Other disorders of carbohydrate metabolism
E74.0Glycogen storage disease
E74.03Cori disease

Inclusion Terms

Official
  • Forbes disease
  • Type III glycogen storage disease

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E74.03 in this effective period.

Related Child Codes

Official
E74.00Glycogen storage disease, unspecified
E74.01von Gierke disease
E74.02Pompe disease
E74.04McArdle disease
E74.05Lysosome-associated membrane protein 2 [LAMP2] deficiency

Includes

Official

ICD-10-CM does not list Includes notes for E74.03 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for E74.03 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E74.03 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E74.03 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E74.03 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Confirmed diagnosis of Cori disease, Forbes disease, or GSD Type III
Enzyme assay or genetic testing confirming debranching enzyme deficiency
Subtype specification if documented (IIIa — liver and muscle; IIIb — liver only)
Physical exam findings including hepatomegaly and muscle weakness assessment

MEAT Support

HCC Buddy guidance
Confirmed diagnosis of Cori disease, Forbes disease, or GSD Type III
Enzyme assay or genetic testing confirming debranching enzyme deficiency
Subtype specification if documented (IIIa — liver and muscle; IIIb — liver only)
Physical exam findings including hepatomegaly and muscle weakness assessment

Audit Caution

HCC Buddy guidance
Confusing Cori disease (Type III) with von Gierke disease (Type I) — both cause hepatomegaly but have different enzyme deficiencies
Not specifying the subtype (IIIa vs IIIb) in documentation when available
Coding only the liver disease or myopathy without identifying the underlying GSD
Missing late-onset cardiac complications that develop in adult patients with GSD III

Common Mistakes

HCC Buddy guidance
E74.01 — von Gierke disease (Type I): also causes hepatomegaly and hypoglycemia but involves different enzyme
E74.00 — Glycogen storage disease, unspecified: do not use when Cori disease is confirmed
E74.04 — McArdle disease (Type V): pure muscle GSD without liver involvement
E74.09 — Other glycogen storage disease: for GSD types without individual codes

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is E74.03 an HCC code?

Yes. E74.03 maps to Glycogen/Amino-Acid/Other Metabolic Disorders under the CMS-HCC V28 risk adjustment model (and Other Significant Endocrine and Metabolic Disorders under V24).

HCC Category Mapping

V28HCC 50, Glycogen/Amino-Acid/Other Metabolic Disorders
0.289
V24HCC 23, Other Significant Endocrine and Metabolic Disorders
0.230
ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders
0.000
RxHCCHCC 43, Other Significant Endocrine and Metabolic Disorders
0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for E74.03

For E74.03to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • 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

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed E74.03 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

E74.03 is the ICD-10-CM diagnosis code for cori disease. A rare inherited metabolic disorder where the body cannot properly process glycogen due to debranching enzyme deficiency, causing muscle weakness and liver problems. E74.03 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

Under the CMS-HCC V28 risk adjustment model, E74.03 maps to Glycogen/Amino-Acid/Other Metabolic Disorders (HCC 50) with a community, non-dual, aged base RAF weight of 0.289. Under the older CMS-HCC V24 model, E74.03 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.230. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Also known as Forbes disease; document presence of hepatomegaly and muscle symptoms. Because E74.03 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for E74.03 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Also known as Forbes disease; document presence of hepatomegaly and muscle symptoms
  • •This condition typically has a better prognosis than other glycogen storage diseases

Clinical Significance

Cori disease (Glycogen Storage Disease Type III), also known as Forbes disease, is caused by glycogen debranching enzyme deficiency. It primarily affects the liver and muscles, causing hepatomegaly, hypoglycemia, and progressive myopathy. While generally milder than von Gierke disease, it can lead to liver cirrhosis and cardiomyopathy in adulthood. Accurate capture ensures risk adjustment reflects the ongoing monitoring and dietary management needs.

Documentation Requirements

  • ✓Confirmed diagnosis of Cori disease, Forbes disease, or GSD Type III
  • ✓Enzyme assay or genetic testing confirming debranching enzyme deficiency
  • ✓Subtype specification if documented (IIIa — liver and muscle; IIIb — liver only)
  • ✓Physical exam findings including hepatomegaly and muscle weakness assessment
  • ✓Laboratory values including creatine kinase, liver enzymes, and fasting glucose
  • ✓Current dietary management and monitoring plan

Commonly Confused Codes

  • •E74.01 — von Gierke disease (Type I): also causes hepatomegaly and hypoglycemia but involves different enzyme
  • •E74.00 — Glycogen storage disease, unspecified: do not use when Cori disease is confirmed
  • •E74.04 — McArdle disease (Type V): pure muscle GSD without liver involvement
  • •E74.09 — Other glycogen storage disease: for GSD types without individual codes
  • •K76.89 — Other specified diseases of liver: hepatic complications should be coded separately

Child Codes

E74.00Glycogen storage disease, unspecified
HCC 50
E74.01von Gierke disease
HCC 50
E74.02Pompe disease
HCC 49
E74.03Cori disease
HCC 50
E74.04McArdle disease
HCC 50
E74.05Lysosome-associated membrane protein 2 [LAMP2] deficiency
HCC 50
E74.09Other glycogen storage disease
HCC 50

Code Hierarchy

└E74Other disorders of carbohydrate metabolism└E74.0Glycogen storage disease└E74.03Cori disease
└E74.03Cori disease

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