How and When to Use Health Factors Z Codes: Z00-Z99

  • How and When to Use Health Factors Z Codes: Z00-Z99

    Posted by Peter Lewis on October 25, 2022 at 1:59 pm

    Z codes are a special group of codes provided in ICD-10-CM for the reporting of factors influencing health status and contact with health services. Z codes (Z00–Z99) are diagnosis codes used for situations where patients don’t have a known disorder. Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed.

    What is the Importance of Z Codes?

    Z codes, found in Chapter 21: Factors Influencing Health Status and Contact with Health Services (Z00-Z99) of the ICD-10-CM code book, may be used in any healthcare setting. The ICD-10-CM Guidelines for Coding and Reporting instruct us to code for all coexisting comorbidities, especially those part of medical decision-making (MDM).

    Common Z Codes for Therapists

    Common Z Codes for Therapists

    General Guidelines on Z Codes

    The first character for all codes in Chapter 21 is always “Z”.


    • Z codes can be used in any healthcare setting
    • Z codes may be used as either a principal or first‐listed diagnosis or a secondary diagnosis, depending on the circumstances of the encounter.
    • Z codes indicate the reason for the encounter.

    Z Codes and Value-Based Reimbursement

    Besides their impact on population health, the data collected by Z codes may also contribute to success under value-based reimbursement models, in large part due to their granular nature. The Health Affairs study noted that social determinant data can inform the design of two distinct types of alternative payment models:


    • Performance-based incentive payments.
    • Penalties, and population-based payments.


    Z codes may be assigned as appropriate to further explain the reasons for presenting to healthcare services, including transfers between healthcare facilities. The ICD-10-CM Official Guidelines for Coding and Reporting identify which codes may be assigned as principal or first-listed diagnosis only, secondary diagnosis only, or principal/first-listed or secondary.

    Z codes are designated as the principal/first listed diagnosis in specific situations such as:

    • To indicate that a person with a resolving disease, injury or chronic condition is being seen for specific aftercare, such as the removal of internal fixation devices such as orthopedic pins.
    • To indicate that a person is seen for the sole purpose of special therapy, such as chemotherapy, immunotherapy and radiation therapy.
    • To indicate that a person not currently ill is encountering the health service for a specific reason, such as to act as an organ donor, encounter for medical observation for suspected diseases and conditions ruled out, administrative examinations (pre-employment exam, recruitment to armed forces), plastic and reconstructive surgery following medical procedures or healed injury (breast reconstruction following mastectomy).
    • To indicate the birth status of newborns.
    Peter Lewis replied 1 year, 8 months ago 1 Member · 0 Replies
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