10ICD Code Hub

Z28.31

Header — not billable

Underimmunization for COVID-19 status

The ICD-10 code for underimmunization for covid-19 status is Z28.31.

Z28.31 is a non-billable header code. It groups related conditions but cannot be used on its own for reimbursement — select one of the 2 more specific codes below.

Documentation support

General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.

Child codes under Z28.31

Related codes in this category