What is the ICD-10 (International Classification of Diseases, 10th Revision) code for checking immunization timers?

ICD-10 Code for Checking Immunization Status

Use ICD-10 code Z23 for encounters specifically for immunization administration, or Z01.84 for encounters to assess immunization status without vaccine administration.

Primary Codes for Immunization-Related Encounters

• Z23 is the appropriate code when the encounter is for the administration of a prophylactic immunization 1
• Z01.84 (Encounter for antibody response examination) can be used when checking immunity status or titers without administering vaccines 1
• These codes fall under the "Z codes" category, which are used for encounters for circumstances other than disease or injury 2, 3

When to Use Each Code

• Use Z23 when:

  • The patient presents specifically to receive one or more vaccines 1
  • The encounter includes reviewing immunization records and administering needed vaccines 1
  • Standing orders for immunizations are being implemented 1

• Use Z01.84 when:

  • The encounter is solely to review immunization records without vaccine administration 1
  • Checking antibody titers to determine immunity status 1
  • Assessing whether catch-up immunizations are needed before scheduling a future vaccine visit 1

Additional Relevant Codes

• Z28.0-Z28.9 series can be used to document reasons for immunization not being carried out, such as:
  • Z28.01: Immunization not carried out because of acute illness 1
  • Z28.1: Immunization not carried out because of patient decision 1
  • Z28.82: Immunization not carried out because of caregiver refusal 1

Clinical Context and Documentation

• Immunization registries (immunization information systems) should be used to track vaccination status, and these encounters should be documented with appropriate ICD-10 codes 1
• The immunization status should be reviewed at each patient visit, making these codes frequently applicable in primary care settings 1
• Reminder/recall systems that prompt these encounters are evidence-based strategies to improve immunization coverage 1

Important Coding Considerations

• ICD-10 codes have significantly greater granularity than ICD-9, with over 141,000 codes compared to less than 20,000 in ICD-9 4
• The positive predictive value of ICD-10 codes varies by condition, with specificity and negative predictive values consistently high across most applications 2
• When coding for specific vaccine-related adverse events (such as anaphylaxis), more specific codes like T80.5 may be required 5