ICD-10 recognizes that the type of vaccine you report with a CPT or HCPCS code gives sufficient detail about the type of immunization the patient needed. So rather than having you provide individual diagnosis codes for each vaccine, ICD-10 allows you to report code Z23 for an encounter involving immunization regardless of the type or number of vaccines. This is especially advantageous when reporting multiple childhood immunizations. Even influenza immunization coding is simplified. Under ICD-9, you have to report V04.81 for the influenza vaccine alone or V06.6 if you provide both the influenza vaccine and the pneumonia vaccine on the same date. Under ICD-10, you simply report code Z23 regardless of how many or what types of vaccines are administered.
The Z23 code includes the following note: “Code first any routine childhood examination.” Therefore, when you provide immunizations in conjunction with a well-child visit, a code for routine child health examination should be reported first, followed by Z23 for any immunizations. This is similar to ICD-9 rules.