What is ICD-10 code E77.8?

E77.8 is the ICD-10-CM diagnosis code for Other disorders of glycoprotein metabolism. Other rare metabolic disorders affecting how the body processes glycoproteins that don't fit into more specific categories. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E77.8 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E77.8 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. E77.8 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. E77.8 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 E77.8 map to under V28?

E77.8 does not map to a CMS-HCC V28 payment category. Check the current CMS-HCC V28 model file for payment year 2026 rather than an older V24 tip sheet.

What does E77.8 pay in RAF?

E77.8 has no separately stated V28 community RAF weight. If it is not a V28 payment HCC, it adds nothing to a community RAF score.

What is the V28 vs V24 difference for E77.8?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. E77.8 was a payment HCC under V24 (Other Significant Endocrine and Metabolic Disorders) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

2026 ICD-10-CM E77.8: Other disorders

E77.8 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

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

Code lookupE77.8Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

E77.8

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

Other disorders of glycoprotein metabolism

Other rare metabolic disorders affecting how the body processes glycoproteins that don't fit into more specific categories.

Buddy Insight

Other disorders of glycoprotein metabolism captures glycoprotein metabolism conditions not classified in E77.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.194

ACA/HHS

Mapped

HCC 27

HHS-HCC 27

Varies by metal level

ESRD/PACE

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.036

RXHCC

Mapped

HCC 43

Other Significant Endocrine a...

RAF 0.063

Code Book Path

Official

E77Disorders of glycoprotein metabolism

E77.8Other disorders of glycoprotein metabolism

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for E77.8 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E77.8 in this effective period.

Related Child Codes

Official

E77.0Defects in post-translational modification of lysosomal enzymes

E77.1Defects in glycoprotein degradation

E77.9Disorder of glycoprotein metabolism, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for E77.8 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for E77.8 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E77.8 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E77.8 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E77.8 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Specific glycoprotein metabolism disorder documented (e.g., congenital disorder of glycosylation, specific CDG type)

Confirmatory testing: isoelectric focusing of transferrin, enzyme assays, or genetic testing

Multi-system involvement assessment: neurological, hepatic, coagulation, endocrine

Current treatment plan and nutritional support needs

MEAT Support

HCC Buddy guidance

Specific glycoprotein metabolism disorder documented (e.g., congenital disorder of glycosylation, specific CDG type)

Confirmatory testing: isoelectric focusing of transferrin, enzyme assays, or genetic testing

Multi-system involvement assessment: neurological, hepatic, coagulation, endocrine

Current treatment plan and nutritional support needs

Audit Caution

HCC Buddy guidance

Not recognizing that congenital disorders of glycosylation (CDG) are coded to E77.8

Using unspecified E77.9 when the provider documents a named glycoprotein disorder

Confusing glycoprotein metabolism disorders with glycogen or carbohydrate metabolism disorders

Failing to capture the multi-system manifestations of CDG as additional diagnosis codes

Common Mistakes

HCC Buddy guidance

E77.0 — Defects in post-translational modification of lysosomal enzymes: specifically for mucolipidoses

E77.1 — Defects in glycoprotein degradation: for conditions like mannosidosis and fucosidosis

E77.9 — Disorder of glycoprotein metabolism, unspecified: avoid when a specific disorder is documented

E74.8 — Other specified disorders of carbohydrate metabolism: CDG may overlap with carbohydrate metabolism issues

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 E77.8 an HCC code?

Yes. E77.8 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.

Code: E77.8
Description: Other disorders of glycoprotein metabolism
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

V24HCC 23, Other Significant Endocrine and Metabolic Disorders

0.194

ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders

0.036

RxHCCHCC 43, Other Significant Endocrine and Metabolic Disorders

0.063

Each model's RAF is its CMS base weight for that model's standard population, so 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 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.

Work E77.8 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for E77.8

For E77.8 to 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 E77.8 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E77.8 is the ICD-10-CM diagnosis code for other disorders of glycoprotein metabolism. Other rare metabolic disorders affecting how the body processes glycoproteins that don't fit into more specific categories. E77.8 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 older CMS-HCC V24 model, E77.8 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.194. 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.

Use this code only when the specific glycoprotein metabolism disorder is not classifiable elsewhere. Because E77.8 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 E77.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code only when the specific glycoprotein metabolism disorder is not classifiable elsewhere
•Document the clinical presentation and any identified metabolic abnormalities

Clinical Significance

Other disorders of glycoprotein metabolism captures glycoprotein metabolism conditions not classified in E77.0 or E77.1, including congenital disorders of glycosylation (CDG) and other rare glycosylation pathway defects. These multi-system disorders can cause neurological impairment, coagulopathy, hepatic dysfunction, and growth failure.

Documentation Requirements

✓Specific glycoprotein metabolism disorder documented (e.g., congenital disorder of glycosylation, specific CDG type)
✓Confirmatory testing: isoelectric focusing of transferrin, enzyme assays, or genetic testing
✓Multi-system involvement assessment: neurological, hepatic, coagulation, endocrine
✓Current treatment plan and nutritional support needs
✓Provider assessment distinguishing this from conditions in E77.0 and E77.1

Commonly Confused Codes

•E77.0: Defects in post-translational modification of lysosomal enzymes: specifically for mucolipidoses
•E77.1: Defects in glycoprotein degradation: for conditions like mannosidosis and fucosidosis
•E77.9: Disorder of glycoprotein metabolism, unspecified: avoid when a specific disorder is documented
•E74.8: Other specified disorders of carbohydrate metabolism: CDG may overlap with carbohydrate metabolism issues