ICD10BillableValid for clinical use

ICD-10 Code Z28.39: Other underimmunization status

Z28.39 is a billable ICD-10 diagnosis code used to classify Other underimmunization status in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Factors influencing health status and contact with health services (Z00-Z99).

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Factors influencing health status and contact with health services (Z00-Z99).

When is it used?

  • May be used when a clinician documents other underimmunization status in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
21Factors influencing health status and contact with health services (Z00-Z99)
block
Z20-Z29Persons with potential health hazards related to communicable diseases
category
Z28Immunization not carried out and underimmunization status
category
Z28.3Underimmunization status
currentZ28.3

Official coding notes

Inclusion terms
  • Delinquent immunization status
  • Lapsed immunization schedule status

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

General Physician

Coding guidelines

Common synonyms

Other underimmunization status

Frequently asked questions

Code details

CodeZ28.39
SystemICD10
Display nameOther underimmunization status
ChapterFactors influencing health status and contact with health services (Z00-Z99)
BlockPersons with potential health hazards related to communicable diseases

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Delinquent immunization statusLapsed immunization schedule statusStatus(post)Status(post)Status(post)Underimmunization status

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code Z28.39 for Other underimmunization status | HealthAssure