Question 1

What is ICD-10 code E77?

Accepted Answer

E77 is the ICD-10-CM diagnosis code for disorders of glycoprotein metabolism. E77 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

Header codes like E77 cannot be reported on claims directly; they organize child codes that share clinical context. Coders should select the billable child code that matches the documented presentation and then verify its current source-backed HCC mapping. Do not infer a child code or risk adjustment value from the header alone.

Question 2

Is E77 an HCC code?

Accepted Answer

E77 is a non-billable header code, so it cannot itself be a payment HCC. Header codes organize more specific child codes that share the same root concept; one of those children may map to a payment HCC under the CMS-HCC V28 or V24 risk adjustment model. Coders should select a child code from the E77 hierarchy that matches the documented presentation, then check that specific child for HCC status.

Question 3

Is E77 billable?

Accepted Answer

No. E77 is a header (non-billable) ICD-10-CM code. Header codes sit at a higher level of the diagnosis hierarchy and exist to organize a family of more specific child codes. Per ICD-10-CM coding guidelines, a header code cannot be reported on a claim as the diagnosis, coders must select a billable child code from the E77 hierarchy that matches the highest level of specificity supported by the provider's documentation. Payers reject header codes submitted as the primary diagnosis.

Question 4

Which HCC does E77 map to under V28?

Accepted Answer

E77 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.

Question 5

What RAF reference is published for E77?

Accepted Answer

E77 has no separately stated V28 community reference coefficient. Check the current CMS mapping and factor files before using it in any member-score workflow.

Question 6

What documentation supports E77?

Accepted Answer

E77 is not a CMS-HCC payment code, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

HCC Buddy Code Card

E77

Get the V28 mapping + MEAT cheat sheet

What This Code Means

Child Codes

Code Hierarchy

Work E77 in HCC Buddy

E77 ICD-10-CM Code: Disorders of glycoprotein metabolism