E77.9 ICD-10-CM Code: Disorder of glycoprotein metabolism, unspecified
HCC Buddy Code Card
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)
E77.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceDisorder of glycoprotein metabolism, unspecified
A metabolic disorder affecting glycoprotein processing in the body, but the specific type has not been determined or specified.
Buddy Insight
Disorder of glycoprotein metabolism, unspecified indicates a confirmed glycoprotein metabolism problem without sufficient documentation to assign a specific code.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
MappedHCC 23
RAF 0.230
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 23
RAF 0.0
RXHCC
MappedHCC 43
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for E77.9 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for E77.9 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E77.9 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for E77.9 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for E77.9 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for E77.9 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for E77.9 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 E77.9 an HCC code?
Yes. E77.9 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.
HCC Category Mapping
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 E77.9
For E77.9to 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 E77.9 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
E77.9 is the ICD-10-CM diagnosis code for disorder of glycoprotein metabolism, unspecified. A metabolic disorder affecting glycoprotein processing in the body, but the specific type has not been determined or specified. E77.9 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, E77.9 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.
This is a catch-all code; attempt to obtain more specific diagnosis before coding. Because E77.9 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 E77.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a catch-all code; attempt to obtain more specific diagnosis before coding
- •Query provider if additional testing or clinical findings could clarify the specific glycoprotein disorder
Clinical Significance
Disorder of glycoprotein metabolism, unspecified indicates a confirmed glycoprotein metabolism problem without sufficient documentation to assign a specific code. This code should prompt queries for additional diagnostic detail since glycoprotein disorders vary widely in severity and treatment needs.
Documentation Requirements
- ✓Provider documentation confirming a glycoprotein metabolism disorder
- ✓Clinical evidence supporting the diagnosis (abnormal glycoprotein levels, clinical features)
- ✓Reason specificity is lacking (workup in progress, indeterminate results)
- ✓Plan for further diagnostic evaluation
- ✓Current symptom management and follow-up
Commonly Confused Codes
- •E77.0: Defects in post-translational modification: for mucolipidoses (I-cell disease, pseudo-Hurler polydystrophy)
- •E77.1: Defects in glycoprotein degradation: for mannosidosis, fucosidosis, sialidosis
- •E77.8: Other disorders of glycoprotein metabolism: for CDG and other specified conditions
- •E88.9: Metabolic disorder, unspecified: too broad when glycoprotein involvement is confirmed