Z28.3 — Underimmunization status

Not billable

Is Z28.3 billable?

No — Z28.3 is a non-billable header code. Z28.3 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 3 billable codes beneath Z28.3.

Billable codes under this header

Z28.3 at a glance

Code	Z28.3
Description	Underimmunization status
Billable	No — header code
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027

Use additional code

Report an additional code alongside Z28.3 to fully describe the condition. Z28.3 is sequenced first.

code, if applicable, to identify:
immunization not carried out because of contraindication (Z28.0-)
immunization not carried out because of patient decision for other and unspecified reason (Z28.2-)
immunization not carried out because of patient decision for reasons of belief or group pressure (Z28.1)
immunization not carried out for other reason (Z28.8-)

Code also — inherited from Z28

Two codes may be needed to describe the condition fully. Whether Z28.3 is sequenced first depends on the reason for the encounter.

, if applicable, encounter for immunization safety counseling (Z71.85)

What codes fall under Z28.3? (2)

How long has Z28.3 existed?

Z28.3 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

FY2023: Z28.3 stopped being billable

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.