Z88.9
BillableAllergy status to unspecified drugs, medicaments and biological substances
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Z88.9 an HCC code?
No. Z88.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
Z88.9 is the ICD-10-CM diagnosis code for allergy status to unspecified drugs, medicaments and biological substances. A patient has a known allergy to one or more drugs, medications, or biological substances, but the specific substance causing the allergy is not documented or specified. Z88.9 sits in the ICD-10-CM chapter for factors influencing health status and contact with health services (z00-z99), within the section covering persons with potential health hazards related to family and personal history and certain conditions influencing health status (z77-z99).
Z88.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Use this code only when the specific allergen cannot be identified; if the allergen is known, use a more specific Z88 code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Z88.9 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 allergen cannot be identified; if the allergen is known, use a more specific Z88 code
- •This is a status code used for documentation purposes and should be included in the patient's allergy history