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Using ICD-10-CM Z-codes

By:  Evan M. Gwilliam DC MBA BS CPC CCPC NCICS CCCPC CPC-I MCS-P CPMA, Christine Woolstenhulme, CMRS
Published:  November 13th, 2015

Chapter 21 of ICD-10-CM is titled "Factors Influencing Health Status and Contact with Health Services".  They cover codes in the categories from Z00 to Z99.  This chapter is used for encounters with health care providers where the patients have no current illnesses or injury.  For example, a patient may present at a clinic because they were around a bunch of sick people, and they want to make sure they did not catch the disease.  The Z20 category is contact with and (suspected) exposure to communicable diseases.  A code from this category would show that the patient is not ill, but clearly has a good reason to be in the doctor's office.

These codes can be used in any healthcare setting, and they may be the first listed diagnosis, or a secondary code, depending on the circumstances.  Z codes do not replace procedure codes.  For example, the appropriate CPT code would still need to be reported along with Z23 Encounter for immunization.

Z codes are broken into the following groups:

  • Contact with, and suspected exposure to communicable diseases and other health hazards
  • Inoculations and vaccinations
  • Status, such as presence of a prosthetic or mechanical device.  This is different from a history code because history codes are for conditions that are no longer present.
  • History, personal or family.
    • Personal history codes may be used in conjunction with follow-up codes.
    • Family history codes may be associated with screening codes.
  • Screening, such as testing seemingly well individuals for early detection of things like parasitic diseases or neoplasms.  The code may be first, or used as an additional code.
  • Observation, which is used rarely for suspected diseases that are being ruled out.
  • Aftercare, which is for continued care during the healing or recovery phase, or long-term consequences of a disease (not to be used for injuries, which have the seventh character for "subsequent encounter")
  • Follow up, which is used to explain continued surveillance following completed treatment for a condition that no longer exists.  
  • Donors of organs and tissues
  • Counseling, such as genetic or childbirth instruction
  • Obstetrical and reproductive services, when none of the complications listed in the obstetrics chapter apply.
  • Newborns and infants, to record the birth
  • Routine and administrative examinations, such as annual check ups.
  • Miscellaneous
  • Nonspecific Z codes

According to guideline 1;C.21.c.16 there are 20 Z-codes that may only be reported as the principal/first listed diagnosis, except when there are multiple encounters on the same day and the medical records for the encounters are combined.


92004 Ophthalmological services: medical examination and evaluation with initiation of diagnostic and treatment program; comprehensive, new patient

You would use a Z-Code for the eye exam:

Z01.00 Encounter for examination of eyes and vision without abnormal findings.  This code would be appropriate for refractive disorders.

Z01.01 Encounter for examination of eyes and vision with abnormal findings. An additional code would be reported to identify the abnormal finding.  This is in addition to refractive disorders.

Another example:

A patient was seen for a routine physical examination, 99395 Periodic comprehensive preventive medicine reevaluation and management. An acceptable diagnosis code to use would be:

Z00.00 Encounter for general adult medical examination without abnormal findings. This patient might have come in for an annual wellness exam. 



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