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Z28.31

Non-billable

Underimmunization for COVID-19 status

Z28.31 is the ICD-10-CM code for Underimmunization for COVID-19 status. It is a non-billable category code — use a more specific child code such as Z28.310 for billing.

Status
Header (non-billable)
Chapter
Z00-Z99
Parent
Z28.3
Subcodes
2
Edition
FY2026

Z00-Z99 Factors influencing health status and contact with health services

Notes

  • •These codes should not be used for individuals who are not eligible for the COVID-19 vaccines, as determined by the healthcare provider.

Frequently asked questions

What is ICD-10 code Z28.31?
Z28.31 is the ICD-10-CM code for "Underimmunization for COVID-19 status". It falls under Z00-Z99 Factors influencing health status and contact with health services.
Is Z28.31 a billable code?
No — Z28.31 is a non-billable header code. Use a more specific child code (such as Z28.310) for billing.
What are the subcodes of Z28.31?
Z28.31 has 2 more specific child codes, including Z28.310, Z28.311.

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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