Revenue Cycle Insider

Hint: Pay attention to ICD-10-CM notes.

The difference between coding Z23 (Encounter for immunization) and using a code from Z28.- (Immunization not carried out and underimmunization status) could not be clearer. As the descriptors note, when a child comes to your practice for an immunization and your provider carries out that immunization without a hitch, you’ll use Z23. And if, for some reason, the provider does not administer the immunization, you’ll look to a code from Z28.- to explain why that immunization could not go ahead.

Sounds straightforward, right? Well, code assignment for these encounters is not quite so black and white. The Z28.- codes are accompanied by numerous instructional notes, which you’ll need to follow to a T if you are to code these kinds of encounters correctly. So, it’s no wonder that the codes provoke some questions.

Fortunately, we’ve assembled all the answers you need below for accurate vaccination code assignment, no matter what happens in the immunization encounter. 

Question: What else do I need to document in addition to Z23 when the provider carries out a successful immunization?

Answer: Before you use Z23, be sure you follow these instructions:

• Code first any routine childhood examination with Z00.121 (Encounter for routine child health examination with abnormal findings) or Z00.129 (Encounter for routine child health examination without abnormal findings). This complies with ICD-10-CM guideline I.C.21.c.2, which says “Code Z23 may be used as a secondary code if the inoculation is given as a routine part of preventive health care, such as a well-baby visit.”
• Code also immunization safety counseling with Z71.85 (Encounter for immunization safety counseling) if applicable.

However, before you use Z71.85, be sure you understand when you should apply the code. ICD-10 is explicit in its definition of safety counseling: Per ICD-10 guideline I.C.21.c.10, the code only applies “for counseling of the patient or caregiver regarding the safety of a vaccine” (emphasis added). The guideline also tells you that the code “should not be used for the provision of general information regarding risks and potential side effects during routine encounters for the administration of vaccines.”

Remember to add:

• An appropriate evaluation and management (E/M) code, such as one from 99391-99393 (Periodic comprehensive preventive medicine reevaluation and management of an individual …)
• The applicable CPT^Ò code for the vaccine(s) administered
• The applicable immunization administration code, such as 90460 (Immunization administration through 18 years of age via any route of administration, with counseling by physician or other qualified health care professional; first or only component of each vaccine or toxoid administered)

Question: What are the differences between the Z28.2- codes?

Answer: When a patient refuses an immunization for a reason other than the patient’s health or religious/social belief, you have three choices of codes to document the refusal:

• Z28.20 (Immunization not carried out because of patient decision for unspecified reason)
• Z28.21 (Immunization not carried out because of patient refusal)
• Z28.29 (Immunization not carried out because of patient decision for other reason)

Each code has a specific application. You would use Z28.20 when the patient has not specifically stated their refusal; Z28.21 when the patient has stated their refusal but has not given a reason for it; and Z28.29 when the patient has provided a reason for the refusal, but another code does not adequately capture that reason. For example, you would use Z28.29 if a patient tells the doctor they are perfectly healthy, and they believe the vaccination is unnecessary.

Note that your application of a Z28.2- code implies the patient is old enough to make their own decision about the immunization. If they are not, you will use Z28.82 (Immunization not carried out because of caregiver refusal).

Don’t forget: Even if the encounter does not result in the patient being vaccinated, if your provider provides vaccination safety counseling at the session, you’ll still report Z71.85.

Question: Who gets to decide immunization refusal due to religious or political belief — the patient or the patient’s parent or guardian?

Answer: Even though the wording of the code descriptor for Z28.1 (Immunization not carried out because of patient decision for reasons of belief or group pressure) suggest it is the patient’s decision that drives code choice, the American Academy of Pediatrics (AAP) has advised that the inclusion term for, “Immunization not carried out because of religious belief,” indicates that it can be used with or without the patient’s decision being known.

This is corroborated by the Excludes1 note accompanying Z28.82, which states you should default to Z28.1 for “immunization not carried out because of caregiver refusal because of religious belief.”

Question: When do I use Z28.3?

Answer: When a patient has not received all the immunizations appropriate to their age, you should document that status with Z28.3 (Underimmunization status). However, the problem with using Z28.3 is that ICD-10 does not tell you how or when to apply it. So, you will need to defer to your pediatrician before using it. Chances are, they will consult an immunization schedule, such as the one provided by the Centers for Disease Control and Prevention (CDC), to make the determination.

Bruce Pegg, BA, MA, CPC, CFPC, Managing Editor, AAPC