Z Codes: Who’s on the First?

Z Codes: Who’s on the First?

Encounter codes require knowing sequencing guidelines and Medicare exceptions.

When applied correctly, Z codes improve claims accuracy and specificity, and help to establish medical necessity for treatment. That’s reason enough to get to know them better.

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). It’s a good idea to review all 16 categories in Chapter 21 of the guidelines:

  1. Contact/Exposures
  2. Inoculations and vaccinations
  3. Status
  4. History (of)
  5. Screening
  6. Observation
  7. Aftercare
  8. Follow Up
  9. Donor
  10. Counseling
  11. Encounters for obstetrical and reproductive services
  12. Newborns and infants
  13. Routine and administrative examinations
  14. Miscellaneous Z codes
  15. Nonspecific Z codes
  16. Z codes that may only be principal/first-listed diagnosis

Z Codes as Principal, First-listed Diagnosis

Some Z codes are reported only as a primary diagnosis. ICD-10-CM guidelines list which Z codes are reportable only as the first listed diagnosis, with exception (Note: Italics are added for emphasis, bold text is in the original guidelines):

The following Z codes/categories 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:

Z00        Encounter for general examination without complaint, suspected or reported diagnosis

Except: Z00.6
Encounter for examination for normal comparison and control in clinical research program

Z01        Encounter for other special examination without complaint, suspected or reported diagnosis

Z02        Encounter for administrative examination

Z03        Encounter for medical observation for suspected diseases and conditions ruled out

Z04        Encounter for examination and observation for other reasons

Z33.2     Encounter for elective termination of pregnancy

Z31.81   Encounter for male factor infertility in female patient

Z31.82   Encounter for Rh incompatibility status

Z31.83   Encounter for assisted reproductive fertility procedure cycle

Z31.84   Encounter for fertility preservation procedure

Z34        Encounter for supervision of normal pregnancy

Z39        Encounter for maternal postpartum care and examination

Z38        Liveborn infants according to place of birth and type of delivery

Z40        Encounter for prophylactic surgery

Z42        Encounter for plastic and reconstructive surgery following medical procedure or healed injury

Z51.0     Encounter for antineoplastic radiation therapy

Z51.1-    Encounter for antineoplastic chemotherapy and immunotherapy

Z52        Donors of organs and tissues

Except: Z52.9 Donor of unspecified organ or tissue

Z76.1     Encounter for health supervision and care of foundling

Z76.2     Encounter for health supervision and care of other healthy infant and child

Z99.12   Encounter for respirator [ventilator] dependence during power failure

Some payers prefer that you report the condition of the patient scheduled for surgery as the primary code, with Z01.818 Encounter for other preprocedural examination as secondary. Check payer policies for pre-op billing guidelines.

As another example, Medicare will not pay a laboratory claim if Z00.00 Encounter for general adult medical examination without abnormal findings is submitted for rendered services. According to Medicare policy (Medicare National Coverage Determinations (NCD) Coding Policy Manual and Change Report (ICD-10-CM) *October 2017):

This section lists codes that are never covered by Medicare for a diagnostic lab testing service. If a code from this section is given as the reason for the test, the test may be billed to the Medicare beneficiary without billing Medicare first because the service is not covered by statue, in most instances because it is performed for screening purposes and is not within an exception. The beneficiary, however, does have a right to have the claim submitted to Medicare, upon request.

For a list of Z codes not covered by Medicare for laboratory services, go to: www.cms.gov/Medicare/Coverage/CoverageGenInfo/LabNCDsICD10.html.

Z Codes and Natural Disasters

The Centers for Disease Control and Prevention (CDC) also offers coding guidance linked to current events on its website. For example, earlier this year, the CDC documented a reminder on how to assign X and Z codes for patients needing treatment for conditions connected to hurricanes:

Injuries incurred as a direct result of the hurricane, assign the appropriate code(s) for the injuries, followed by the code X37.0-, Hurricane (with the appropriate seventh character), and any other applicable external cause of injury codes. Code X37.0- also should be assigned when an injury is incurred because of flooding caused by a levee breaking related to the hurricane. Code X38.-, Flood (with the appropriate seventh character), should be assigned when an injury is from flooding resulting directly from the storm.

Z codes (other reasons for healthcare encounters) may be assigned as appropriate to further explain the reasons for presenting for healthcare services, including transfers between healthcare facilities. The ICD-10-CM Official Guidelines for Coding and Reporting identify which codes maybe assigned as principal or first-listed diagnosis only, secondary diagnosis only, or principal/first-listed or secondary (depending on the circumstances). Possible applicable Z codes include: Z59.0 Homelessness, Z59.1 Inadequate housing.


Medicare National Coverage Determinations (NCD) Coding Policy Manual and Change Report (ICD-10-CM): www.cms.gov/Medicare/Coverage/CoverageGenInfo/Downloads/manual201710_ICD10.pdf

ICD-10-CM Coding Advice for Healthcare Encounters in Hurricane Aftermath August 2017: www.cdc.gov/nchs/data/icd/Hurricane_coding_guidance.pdf

Julie Pisacane, CPMA, CPPM, CEMC, CRHC, CCA, is employed at NYU Langone Health as a professional billing compliance specialist. She reviews medical record documentation of new providers and provides in-service training to physicians and staff resulting from the reviews. Pisacane is a member of the Nassau County, N.Y., local  chapter.

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