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v1.0.0
ICD-10 Guide
ICD-10 CodesZ28.3

Z28.3

Underimmunization status

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/12/2025

Code Description

ICD-10 Z28.3 is a billable code used to indicate a diagnosis of underimmunization status.

Key Diagnostic Point:

Z28.3 indicates a status of underimmunization, which refers to individuals who have not received all recommended vaccinations according to established immunization schedules. This status can arise from various factors, including socioeconomic barriers, lack of access to healthcare services, cultural beliefs, and misinformation about vaccines. Preventive care plays a crucial role in addressing underimmunization, as healthcare providers are tasked with educating patients about the importance of vaccinations and ensuring that they receive timely immunizations. Screening for immunization status is essential, particularly in pediatric populations, to identify those at risk of vaccine-preventable diseases. Social determinants of health, such as income, education, and community resources, significantly influence immunization rates and access to healthcare services. Addressing these factors through community outreach and public health initiatives can improve vaccination coverage and overall health outcomes.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variety of factors influencing immunization status (e.g., socioeconomic, cultural)
  • Need for thorough documentation of immunization history
  • Potential for misinterpretation of underimmunization status
  • Variability in immunization schedules across different populations

Audit Risk Factors

  • Inadequate documentation of immunization history
  • Failure to capture social determinants impacting immunization
  • Misuse of Z28.3 when a specific vaccine-related diagnosis is present
  • Inconsistent application of preventive care guidelines

Specialty Focus

Medical Specialties

Primary Care

Documentation Requirements

Document immunization history, patient education efforts, and follow-up plans.

Common Clinical Scenarios

Routine checkups where immunization status is assessed, screenings for vaccine-preventable diseases.

Billing Considerations

Consider social determinants such as access to healthcare and patient education on vaccine importance.

Public Health

Documentation Requirements

Population-level data collection, surveillance of immunization rates, and community outreach efforts.

Common Clinical Scenarios

Epidemiological studies assessing vaccination coverage and preventive health campaigns.

Billing Considerations

Focus on tracking health disparities and implementing strategies to improve immunization rates in underserved populations.

Coding Guidelines

Inclusion Criteria

Use Z28.3 When
  • Z codes are used when a patient is not currently ill but requires attention for a health
  • related issue
  • 3 should be sequenced appropriately, often as a secondary diagnosis when a primary condition is being treated
  • Payer requirements may vary, so it's essential to verify coverage for preventive services

Exclusion Criteria

Do NOT use Z28.3 When
No specific exclusions found.

Related CPT Codes

90460CPT Code

Immunization administration (e.g., vaccines)

Clinical Scenario

Used during visits where immunization status is assessed and vaccines are administered.

Documentation Requirements

Document vaccine type, administration details, and patient consent.

Specialty Considerations

Primary care providers should ensure comprehensive immunization records are maintained.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for greater specificity in coding underimmunization status, enabling better tracking of vaccination rates and identification of barriers to immunization.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for greater specificity in coding underimmunization status, enabling better tracking of vaccination rates and identification of barriers to immunization.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for greater specificity in coding underimmunization status, enabling better tracking of vaccination rates and identification of barriers to immunization.

Resources

Clinical References

  • •
    CDC Immunization Schedules
  • •
    Healthy People 2030 Immunization Goals

Coding & Billing References

  • •
    CDC Immunization Schedules
  • •
    Healthy People 2030 Immunization Goals

Frequently Asked Questions

What documentation is required for Z28.3?

Documentation must include the patient's immunization history, reasons for underimmunization, and any educational efforts made by the provider to address these issues.