Z28.3Underimmunization status

Z28.3 is the ICD-10-CM diagnosis code for underimmunization status. It belongs to category Z28 (immunization not carried out and underimmunization status), block Z20-Z29 (persons with potential health hazards related to communicable diseases) and chapter 21 (factors influencing health status and contact with health services). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

Within Z28 (immunization not carried out and underimmunization status), Z28.3 is specifically for underimmunization status. Related codes cover immunization not carried out because of contraindication (Z28.0), immunization not carried out because of patient decision for reasons of belief or group pressure (Z28.1), immunization not carried out because of patient decision for other and unspecified reason (Z28.2), immunization not carried out for other reason (Z28.8) and immunization not carried out for unspecified reason (Z28.9).

To report this condition, pick the subcode that matches the documentation: Z28.31 (status) and Z28.39 (status).

Use an additional 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) and immunization not carried out for other reason (Z28.8-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015, and changed in FY2022 (expanded into subcodes).

Before ICD-10, this condition was coded in ICD-9-CM as V15.83 (personal history of underimmunization status).