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ICD-10 Guide
ICD-10 CodesZ28.01

Z28.01

Immunization not carried out because of acute illness of patient

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

Code Description

ICD-10 Z28.01 is a billable code used to indicate a diagnosis of immunization not carried out because of acute illness of patient.

Key Diagnostic Point:

Z28.01 is used when a patient is unable to receive an immunization due to an acute illness. This situation often arises in primary care settings where preventive health measures are crucial. The acute illness may range from mild infections to more severe conditions that temporarily compromise the patient's health. Social determinants such as access to healthcare, socioeconomic status, and education can influence the likelihood of immunization. Preventive care is essential in reducing disease incidence, and understanding the barriers to immunization can help healthcare providers address these issues effectively. Documentation must clearly indicate the reason for the delay in immunization, including details about the acute illness and any relevant social factors that may impact the patient's health status and access to care.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Need for detailed documentation of the acute illness.
  • Understanding of social determinants affecting immunization.
  • Differentiation from other Z codes related to immunization.
  • Potential for misinterpretation of the acute illness's severity.

Audit Risk Factors

  • Insufficient documentation of the acute illness.
  • Failure to link the acute illness to the immunization delay.
  • Inconsistent coding practices across providers.
  • Lack of clarity in the patient's health status.

Specialty Focus

Medical Specialties

Primary Care

Documentation Requirements

Documentation must include the nature of the acute illness, its duration, and any recommendations for follow-up immunization.

Common Clinical Scenarios

Patients presenting with acute respiratory infections, gastrointestinal illnesses, or other temporary conditions that prevent vaccination.

Billing Considerations

Consideration of social determinants such as transportation issues or financial barriers that may affect follow-up care.

Public Health

Documentation Requirements

Documentation should include population-level data on immunization rates and the impact of acute illnesses on community health.

Common Clinical Scenarios

Outbreaks of vaccine-preventable diseases where acute illness prevents immunization in a significant portion of the population.

Billing Considerations

Focus on tracking health disparities and barriers to immunization in vulnerable populations.

Coding Guidelines

Inclusion Criteria

Use Z28.01 When
  • Z codes are used to indicate reasons for encounters that are not primarily disease
  • related
  • 01 should be sequenced after the acute illness code
  • Payer requirements may vary, so it is essential to verify specific documentation needs with each payer

Exclusion Criteria

Do NOT use Z28.01 When
No specific exclusions found.

Related CPT Codes

90460CPT Code

Immunization administration

Clinical Scenario

Used when administering vaccines, but may be delayed due to acute illness.

Documentation Requirements

Document the reason for the delay in immunization.

Specialty Considerations

Primary care providers should ensure follow-up for missed immunizations.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has increased specificity in coding, allowing for better tracking of immunization barriers related to acute illnesses.

ICD-9 vs ICD-10

The transition to ICD-10 has increased specificity in coding, allowing for better tracking of immunization barriers related to acute illnesses.

Reimbursement & Billing Impact

The transition to ICD-10 has increased specificity in coding, allowing for better tracking of immunization barriers related to acute illnesses.

Resources

Clinical References

  • •
    CDC Immunization Guidelines

Coding & Billing References

  • •
    CDC Immunization Guidelines

Frequently Asked Questions

When should Z28.01 be used?

Z28.01 should be used when a patient cannot receive an immunization due to an acute illness. Documentation must specify the illness and its impact on the patient's ability to be vaccinated.