ICD-10-CM Code For Encounter For Immunization: Group Overview

The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group Z23 includes codes for encounters where vaccinations or immunizations are administered to prevent communicable diseases, covering routine and recommended vaccines. These ICD-10-CM diagnosis codes are used to document preventive care encounters, capturing the purpose of the visit and the nature of the immunization provided. Accurate coding within the ICD-10-CM Z23 group supports proper claim adjudication.

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ICD-10-CM Z23: Encounter For Immunization Overview

The ICD-10-CM Z23 codes represent encounters for immunizations and vaccinations aimed at preventing infectious diseases. These codes apply to services across the preventative care spectrum, targeting communicable disease prevention rather than treatment of active infection. Accurate coding ensures correct classification of preventive services and supports appropriate reimbursement for immunization administration.

When to Use

Use a code from this group when the patient visit is specifically for receiving an immunization or vaccine. Do not use these codes for treatment of an active infectious disease; they are reserved for preventive vaccination encounters.

ICD-10-CM Codes

1 rows

ICD-10-CM Code	Description
Z23	Encounter for immunization

DRG Codes

2 rows

DRG Code	Description
795	Normal Newborn
951	Other Factors Influencing Health Status

Typical Clinical Scenarios

An adult patient presents to a primary care clinic for routine preventive care and requests seasonal influenza and tetanus booster vaccines. The visit is focused solely on administration of immunizations without any active complaint or new diagnosis; documentation notes immunizations given and consent obtained. A code from the immunization encounter group is assigned to indicate the purpose of the visit. Typical codes: Z23
A young child is brought to a public health clinic for the routine childhood immunization schedule, including DTaP, IPV, and MMR, due to well-child follow-up and school entry requirements. The encounter is for vaccine administration during a scheduled visit rather than evaluation of illness, so the immunization encounter code is used to capture the reason for the visit. Typical codes: Z23
An adult presents to an urgent care solely to receive a post-exposure prophylactic vaccine (e.g., hepatitis B immune prophylaxis after occupational needlestick) and receives the recommended dose during the visit; there is no active infectious disease diagnosis being treated. Because the encounter is primarily for immunization administration, the encounter-for-immunization code is recorded. Typical codes: Z23

Related Codes

Z20-CONTACT-WITH-SUSPECTED-EXPOSURE

ICD-10-CM Code For Contact With And (Suspected) Exposure To Communicable Diseases: Group Overview

Z21-ASYMPTOMATIC-HUMAN-IMMUNODEFICIENCY-VIRUS-INFECTION

ICD-10-CM Code For Asymptomatic Human Immunodeficiency Virus Infection Status: Group Overview

Z22-CARRIER-OF-INFECTIOUS-DISEASE

ICD-10-CM Code For Carrier Of Infectious Disease: Group Overview

Z28-IMMUNIZATION-NOT-CARRIED-OUT

ICD-10-CM Code For Immunization Not Carried Out And Underimmunization Status: Group Overview

Z29-ENCOUNTER-FOR-PROPHYLACTIC-MEASURES

ICD-10-CM Code For Encounter For Other Prophylactic Measures: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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When to Use

ICD-10-CM Codes

1 rows

ICD-10-CM Code	Description
Z23	Encounter for immunization

DRG Codes

2 rows

DRG Code	Description
795	Normal Newborn
951	Other Factors Influencing Health Status

Typical Clinical Scenarios

An adult patient presents to a primary care clinic for routine preventive care and requests seasonal influenza and tetanus booster vaccines. The visit is focused solely on administration of immunizations without any active complaint or new diagnosis; documentation notes immunizations given and consent obtained. A code from the immunization encounter group is assigned to indicate the purpose of the visit. Typical codes: Z23
A young child is brought to a public health clinic for the routine childhood immunization schedule, including DTaP, IPV, and MMR, due to well-child follow-up and school entry requirements. The encounter is for vaccine administration during a scheduled visit rather than evaluation of illness, so the immunization encounter code is used to capture the reason for the visit. Typical codes: Z23
An adult presents to an urgent care solely to receive a post-exposure prophylactic vaccine (e.g., hepatitis B immune prophylaxis after occupational needlestick) and receives the recommended dose during the visit; there is no active infectious disease diagnosis being treated. Because the encounter is primarily for immunization administration, the encounter-for-immunization code is recorded. Typical codes: Z23

Related Codes

Z20-CONTACT-WITH-SUSPECTED-EXPOSURE

ICD-10-CM Code For Contact With And (Suspected) Exposure To Communicable Diseases: Group Overview

Z21-ASYMPTOMATIC-HUMAN-IMMUNODEFICIENCY-VIRUS-INFECTION

ICD-10-CM Code For Asymptomatic Human Immunodeficiency Virus Infection Status: Group Overview

Z22-CARRIER-OF-INFECTIOUS-DISEASE

ICD-10-CM Code For Carrier Of Infectious Disease: Group Overview

Z28-IMMUNIZATION-NOT-CARRIED-OUT

ICD-10-CM Code For Immunization Not Carried Out And Underimmunization Status: Group Overview

Z29-ENCOUNTER-FOR-PROPHYLACTIC-MEASURES

ICD-10-CM Code For Encounter For Other Prophylactic Measures: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

ICD-10-CM Code For Encounter For Immunization: Group Overview

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ICD-10-CM Z23: Encounter For Immunization Overview

ICD-10-CM Code For Encounter For Immunization: Group Overview

Sign up for ICD-10-CM Code For Encounter For Immunization: Group Overview policy alerts

ICD-10-CM Z23: Encounter For Immunization Overview

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

What does the ICD-10-CM code group `Z23` represent?

When should a provider use `Z23` on documentation or a claim?

Does `Z23` apply to treatment of active infections?

How does accurate coding with `Z23` affect claims?

What types of services are captured by the `Z23` encounter for immunization code?

References

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

What does the ICD-10-CM code group `Z23` represent?

When should a provider use `Z23` on documentation or a claim?

Does `Z23` apply to treatment of active infections?

How does accurate coding with `Z23` affect claims?

What types of services are captured by the `Z23` encounter for immunization code?

References