ICD-10 Code for Underimmunization Status

The default ICD-10-CM 2027 code for underimmunization status is Z28.39 – Other underimmunization status. More specific codes depend on the details documented, as listed in the official index (4 codes, 3 billable).

Main code
Z28.39 – Other underimmunization status
Billable
Yes

Index entries for Underimmunization status

How to choose the right code

Start with the main term, then pick the indented subterm that matches the documentation (type, cause, site, laterality, episode of care). Always confirm the code in the tabular list: follow its Excludes1/Excludes2, “code first” and “use additional code” notes, and add a 7th character where required.

Source: CDC/NCHS ICD-10-CM FY2027 alphabetic index.