Question 1

What is ICD-10 code Z88?

Accepted Answer

Z88 is the ICD-10-CM diagnosis code for Allergy status to drugs, medicaments and biological substances. It belongs to the ICD-10-CM chapter for factors influencing health status and contact with health services (z00-z99). Z88 is a non-billable header code that organizes more specific child codes; the actual diagnosis on a claim must use one of those children. Z88 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 Z88 an HCC code?

Accepted Answer

Z88 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 Z88 hierarchy that matches the documented presentation, then check that specific child for HCC status.

Question 3

Is Z88 billable?

Accepted Answer

No. Z88 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 Z88 hierarchy that matches the highest level of specificity supported by the provider's documentation. Payers reject header codes submitted as the primary diagnosis.

Z88

What This Code Means

Excludes 2 — Not included here, may code separately

Child Codes

Code Hierarchy

Open Z88 in the Interactive Encoder