Question 1

What is ICD-10 code H21.30?

Accepted Answer

H21.30 is the ICD-10-CM diagnosis code for Idiopathic cysts of iris, ciliary body or anterior chamber. It belongs to the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59). H21.30 is a non-billable header code that organizes more specific child codes; the actual diagnosis on a claim must use one of those children. H21.30 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.

Question 2

Is H21.30 an HCC code?

Accepted Answer

H21.30 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 H21.30 hierarchy that matches the documented presentation, then check that specific child for HCC status.

Question 3

Is H21.30 billable?

Accepted Answer

No. H21.30 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 H21.30 hierarchy that matches the highest level of specificity supported by the provider's documentation. Payers reject header codes submitted as the primary diagnosis.

HCC Buddy Code Card

H21.30

What This Code Means

Child Codes

Code Hierarchy

Open H21.30 in the Interactive Encoder

H21.30 ICD-10-CM Code: Idiopathic cysts of iris, ciliary body or anterior chamber