Chapter 21: Factors influencing health status and contact with health services (Z00-Z99)

Note: The chapter specific guidelines provide additional information about the use of Z codes for specified encounters.

a. Use of Z codes in any healthcare setting

Z codes are for use in any healthcare setting. Z codes may be used as either a first-listed (principal diagnosis code in the inpatient setting) or secondary code, depending on the circumstances of the encounter. Certain Z codes may only be used as first-listed or principal diagnosis.

b. Z Codes indicate a reason for an encounter

Z codes are not procedure codes. A corresponding procedure code must accompany a Z code to describe any procedure performed.

c. Categories of Z Codes

1) Contact/Exposure

Category Z20 indicates contact with, and suspected exposure to, communicable diseases. These codes are for patients who do not show any sign or symptom of a disease but are suspected to have been exposed to it by close personal contact with an infected individual or are in an area where a disease is epidemic. Category Z77, Other contact with and (suspected) exposures hazardous to health, indicates contact with and suspected exposures hazardous to health. Contact/exposure codes may be used as a first-listed code to explain an encounter for testing, or, more commonly, as a secondary code to identify a potential risk.

2) Inoculations and vaccinations

Code Z23 is for encounters for inoculations and vaccinations. It indicates that a patient is being seen to receive a prophylactic inoculation against a disease. Procedure codes are required to identify the actual administration of the injection and the type(s) of immunizations given. 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.

3) Status

Status codes indicate that a patient is either a carrier of a disease or has the sequelae or residual of a past disease or condition. This includes such things as the presence of prosthetic or mechanical devices resulting from past treatment. A status code is informative, because the status may affect the course of treatment and its outcome. A status code is distinct from a history code. The history code indicates that the patient no longer has the condition. A status code should not be used with a diagnosis code from one of the body system chapters, if the diagnosis code includes the information provided by the status code. For example, code Z94.1, Heart transplant status, should not be used with a code from subcategory T86.2, Complications of heart transplant. The status code does not provide additional information. The complication code indicates that the patient is a heart transplant patient. For encounters for weaning from a mechanical ventilator, assign a code from subcategory J96.1, Chronic respiratory failure, followed by code Z99.11, Dependence on respirator [ventilator] status.

The status Z codes/categories are:

Z14 Genetic carrier

Genetic carrier status indicates that a person carries a gene, associated with a particular disease, which may be passed to offspring who may develop that disease. The person does not have the disease and is not at risk of developing the disease.

Z15 Genetic susceptibility to disease

Genetic susceptibility indicates that a person has a gene that increases the risk of that person developing the disease. Codes from category Z15 should not be used as principal or first-listed codes. If the patient has the condition to which he/she is susceptible, and that condition is the reason for the encounter, the code for the current condition should be sequenced first. If the patient is being seen for follow-up after completed treatment for this condition, and the condition no longer exists, a follow-up code should be sequenced first, followed by the appropriate personal history and genetic susceptibility codes. If the purpose of the encounter is genetic counseling associated with procreative management, code Z31.5, Encounter for genetic counseling, should be assigned as the first-listed code, followed by a code from category Z15. Additional codes should be assigned for any applicable family or personal history.

Z16 Resistance to antimicrobial drugs

This code indicates that a patient has a condition that is resistant to antimicrobial drug treatment. Sequence the infection code first.

Z17 Estrogen receptor status

Z18 Retained foreign body fragments

Z19 Hormone sensitivity malignancy status

Z21 Asymptomatic HIV infection status

This code indicates that a patient has tested positive for HIV but has manifested no signs or symptoms of the disease.

Z22 Carrier of infectious disease

Carrier status indicates that a person harbors the specific organisms of a disease without manifest symptoms and is capable of transmitting the infection.

Z28.3 Underimmunization status

Z33.1 Pregnant state, incidental

This code is a secondary code only for use when the pregnancy is in no way complicating the reason for visit. Otherwise, a code from the obstetric chapter is required.

Z66 Do not resuscitate

This code may be used when it is documented by the provider that a patient is on do not resuscitate status at any time during the stay.

Z67 Blood type

Z68 Body mass index (BMI)

As with all other secondary diagnosis codes, the BMI codes should only be assigned when they meet the definition of a reportable diagnosis (see Section III, Reporting Additional Diagnoses).

Z74.01 Bed confinement status

Z76.82 Awaiting organ transplant status

Z78 Other specified health status

Code Z78.1, Physical restraint status, may be used when it is documented by the provider that a patient has been put in restraints during the current encounter. Please note that this code should not be reported when it is documented by the provider that a patient is temporarily restrained during a procedure.

Z79 Long-term (current) drug therapy

Codes from this category indicate a patient's continuous use of a prescribed drug (including such things as aspirin therapy) for the long-term treatment of a condition or for prophylactic use. It is not for use for patients who have addictions to drugs. This subcategory is not for use of medications for detoxification or maintenance programs to prevent withdrawal symptoms in patients with drug dependence (e.g., methadone maintenance for opiate dependence). Assign the appropriate code for the drug dependence instead. Assign a code from Z79 if the patient is receiving a medication for an extended period as a prophylactic measure (such as for the prevention of deep vein thrombosis) or as treatment of a chronic condition (such as arthritis) or a disease requiring a lengthy course of treatment (such as cancer). Do not assign a code from category Z79 for medication being administered for a brief period of time to treat an acute illness or injury (such as a course of antibiotics to treat acute bronchitis).

Z88 Allergy status to drugs, medicaments and biological substances

Except: Z88.9, Allergy status to unspecified drugs, medicaments and biological substances status

Z89 Acquired absence of limb

Z90 Acquired absence of organs, not elsewhere classified

Z91.0- Allergy status, other than to drugs and biological substances

Z92.82 Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to a current facility

Assign code Z92.82, Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility, as a secondary diagnosis when a patient is received by transfer into a facility and documentation indicates they were administered tissue plasminogen activator (tPA) within the last 24 hours prior to admission to the current facility. This guideline applies even if the patient is still receiving the tPA at the time they are received into the current facility. The appropriate code for the condition for which the tPA was administered (such as cerebrovascular disease or myocardial infarction) should be assigned first. Code Z92.82 is only applicable to the receiving facility record and not to the transferring facility record.

Z93 Artificial opening status

Z94 Transplanted organ and tissue status

Z95 Presence of cardiac and vascular implants and grafts

Z96 Presence of other functional implants

Z97 Presence of other devices

Z98 Other postprocedural states

Assign code Z98.85, Transplanted organ removal status, to indicate that a transplanted organ has been previously removed. This code should not be assigned for the encounter in which the transplanted organ is removed. The complication necessitating removal of the transplant organ should be assigned for that encounter. See section I.C19. for information on the coding of organ transplant complications.

Z99 Dependence on enabling machines and devices, not elsewhere classified

Note: Categories Z89-Z90 and Z93-Z99 are for use only if there are no complications or malfunctions of the organ or tissue replaced, the amputation site or the equipment on which the patient is dependent.

4) History (of)

There are two types of history Z codes, personal and family. Personal history codes explain a patient's past medical condition that no longer exists and is not receiving any treatment, but that has the potential for recurrence, and therefore may require continued monitoring. Family history codes are for use when a patient has a family member(s) who has had a particular disease that causes the patient to be at higher risk of also contracting the disease. Personal history codes may be used in conjunction with follow-up codes and family history codes may be used in conjunction with screening codes to explain the need for a test or procedure. History codes are also acceptable on any medical record regardless of the reason for visit. A history of an illness, even if no longer present, is important information that may alter the type of treatment ordered. The history Z code categories are:

Z80 Family history of primary malignant neoplasm

Z81 Family history of mental and behavioral disorders

Z82 Family history of certain disabilities and chronic diseases (leading to disablement)

Z83 Family history of other specific disorders

Z84 Family history of other conditions

Z85 Personal history of malignant neoplasm

Z86 Personal history of certain other diseases

Z87 Personal history of other diseases and conditions

Z91.4- Personal history of psychological trauma, not elsewhere classified

Z91.5 Personal history of self-harm

Z91.8- Other specified personal risk factors, not elsewhere classified

Exception: Z91.83, Wandering in diseases classified elsewhere

Z92 Personal history of medical treatment

Except: Z92.0, Personal history of contraception. Except: Z92.82, Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to a current facility.

5) Screening

Screening is the testing for disease or disease precursors in seemingly well individuals so that early detection and treatment can be provided for those who test positive for the disease (e.g., screening mammogram). The testing of a person to rule out or confirm a suspected diagnosis because the patient has some sign or symptom is a diagnostic examination, not a screening. In these cases, the sign or symptom is used to explain the reason for the test. A screening code may be a first-listed code if the reason for the visit is specifically the screening exam. It may also be used as an additional code if the screening is done during an office visit for other health problems. A screening code is not necessary if the screening is inherent to a routine examination, such as a pap smear done during a routine pelvic examination. Should a condition be discovered during the screening then the code for the condition may be assigned as an additional diagnosis. The Z code indicates that a screening exam is planned. A procedure code is required to confirm that the screening was performed. The screening Z codes/categories:

Z11 Encounter for screening for infectious and parasitic diseases

Z12 Encounter for screening for malignant neoplasms

Z13 Encounter for screening for other diseases and disorders

Except: Z13.9, Encounter for screening, unspecified

Z36 Encounter for antenatal screening for mother

6) Observation

There are three observation Z code categories. They are for use in very limited circumstances when a person is being observed for a suspected condition that is ruled out. The observation codes are not for use if an injury or illness or any signs or symptoms related to the suspected condition are present. In such cases the diagnosis/symptom code is used with the corresponding external cause code. The observation codes are to be used as principal diagnosis only. The only exception to this is when the principal diagnosis is required to be a code from category Z38, Liveborn infants according to place of birth and type of delivery. Then a code from category Z05, Encounter for observation and evaluation of newborn for suspected diseases and conditions ruled out, is sequenced after the Z38 code. Additional codes may be used in addition to the observation code, but only if they are unrelated to the suspected condition being observed. Codes from subcategory Z03.7, Encounter for suspected maternal and fetal conditions ruled out, may either be used as a first-listed or as an additional code assignment depending on the case. They are for use in very limited circumstances on a maternal record when an encounter is for a suspected maternal or fetal condition that is ruled out during that encounter (for example, a maternal or fetal condition may be suspected due to an abnormal test result). These codes should not be used when the condition is confirmed. In those cases, the confirmed condition should be coded. In addition, these codes are not for use if an illness or any signs or symptoms related to the suspected condition or problem are present. In such cases the diagnosis/symptom code is used. Additional codes may be used in addition to the code from subcategory Z03.7, but only if they are unrelated to the suspected condition being evaluated. Codes from subcategory Z03.7 may not be used for encounters for antenatal screening of mother. See Section I.C.21. Screening. For encounters for suspected fetal condition that are inconclusive following testing and evaluation, assign the appropriate code from category O35, O36, O40 or O41. The observation Z code categories:

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

Z04 Encounter for examination and observation for other reasons

Except: Z04.9, Encounter for examination and observation for unspecified reason

Z05 Encounter for observation and evaluation of newborn for suspected diseases and conditions ruled out

7) Aftercare

Aftercare visit codes cover situations when the initial treatment of a disease has been performed and the patient requires continued care during the healing or recovery phase, or for the long-term consequences of the disease. The aftercare Z code should not be used if treatment is directed at a current, acute disease. The diagnosis code is to be used in these cases. Exceptions to this rule are codes Z51.0, Encounter for antineoplastic radiation therapy, and codes from subcategory Z51.1, Encounter for antineoplastic chemotherapy and immunotherapy. These codes are to be first-listed, followed by the diagnosis code when a patient's encounter is solely to receive radiation therapy, chemotherapy, or immunotherapy for the treatment of a neoplasm. If the reason for the encounter is more than one type of antineoplastic therapy, code Z51.0 and a code from subcategory Z51.1 may be assigned together, in which case one of these codes would be reported as a secondary diagnosis. The aftercare Z codes should also not be used for aftercare for injuries. For aftercare of an injury, assign the acute injury code with the appropriate 7th character (for subsequent encounter). The aftercare codes are generally first-listed to explain the specific reason for the encounter. An aftercare code may be used as an additional code when some type of aftercare is provided in addition to the reason for admission and no diagnosis code is applicable. An example of this would be the closure of a colostomy during an encounter for treatment of another condition. Aftercare codes should be used in conjunction with other aftercare codes or diagnosis codes to provide better detail on the specifics of an aftercare encounter visit, unless otherwise directed by the classification. Should a patient receive multiple types of antineoplastic therapy during the same encounter, code Z51.0, Encounter for antineoplastic radiation therapy, and codes from subcategory Z51.1, Encounter for antineoplastic chemotherapy and immunotherapy, may be used together on a record. The sequencing of multiple aftercare codes depends on the circumstances of the encounter. Certain aftercare Z code categories need a secondary diagnosis code to describe the resolving condition or sequelae. For others, the condition is included in the code title. Additional Z code aftercare category terms include fitting and adjustment, and attention to artificial openings. Status Z codes may be used with aftercare Z codes to indicate the nature of the aftercare. For example code Z95.1, Presence of aortocoronary bypass graft, may be used with code Z48.812, Encounter for surgical aftercare following surgery on the circulatory system, to indicate the surgery for which the aftercare is being performed. A status code should not be used when the aftercare code indicates the type of status, such as using Z43.0, Encounter for attention to tracheostomy, with Z93.0, Tracheostomy status. The aftercare Z category/codes:

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

Z43 Encounter for attention to artificial openings

Z44 Encounter for fitting and adjustment of external prosthetic device

Z45 Encounter for adjustment and management of implanted device

Z46 Encounter for fitting and adjustment of other devices

Z47 Orthopedic aftercare

Z48 Encounter for other postprocedural aftercare

Z49 Encounter for care involving renal dialysis

Z51 Encounter for other aftercare and medical care

8) Follow-up

The follow-up codes are used to explain continuing surveillance following completed treatment of a disease, condition, or injury. They imply that the condition has been fully treated and no longer exists. They should not be confused with aftercare codes, or injury codes with a 7th character for subsequent encounter, that explain ongoing care of a healing condition or its sequelae. Follow-up codes may be used in conjunction with history codes to provide the full picture of the healed condition and its treatment. The follow-up code is sequenced first, followed by the history code. A follow-up code may be used to explain multiple visits. Should a condition be found to have recurred on the follow-up visit, then the diagnosis code for the condition should be assigned in place of the follow-up code. The follow-up Z code categories:

Z08 Encounter for follow-up examination after completed treatment for malignant neoplasm

Z09 Encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm

Z39 Encounter for maternal postpartum care and examination

9) Donor

Codes in category Z52, Donors of organs and tissues, are used for living individuals who are donating blood or other body tissue. These codes are only for individuals donating for others, not for self-donations. They are not used to identify cadaveric donations.

10) Counseling

Counseling Z codes are used when a patient or family member receives assistance in the aftermath of an illness or injury, or when support is required in coping with family or social problems. They are not used in conjunction with a diagnosis code when the counseling component of care is considered integral to standard treatment. The counseling Z codes/categories:

Z30.0- Encounter for general counseling and advice on contraception

Z31.5 Encounter for genetic counseling

Z31.6- Encounter for general counseling and advice on procreation

Z32.2 Encounter for childbirth instruction

Z32.3 Encounter for childcare instruction

Z69 Encounter for mental health services for victim and perpetrator of abuse

Z70 Counseling related to sexual attitude, behavior and orientation

Z71 Persons encountering health services for other counseling and medical advice, not elsewhere classified

Z76.81 Expectant mother prebirth pediatrician visit

11) Encounters for Obstetrical and Reproductive Services

See Section I.C.15. Pregnancy, Childbirth, and the Puerperium, for further instruction on the use of these codes. Z codes for pregnancy are for use in those circumstances when none of the problems or complications included in the codes from the Obstetrics chapter exist (a routine prenatal visit or postpartum care). Codes in category Z34, Encounter for supervision of normal pregnancy, are always first-listed and are not to be used with any other code from the OB chapter. Codes in category Z3A, Weeks of gestation, may be assigned to provide additional information about the pregnancy. Category Z3A codes should not be assigned for pregnancies with abortive outcomes (categories O00-O08), elective termination of pregnancy (code Z33.32), nor for postpartum conditions, as category Z3A is not applicable to these conditions. The date of the admission should be used to determine weeks of gestation for inpatient admissions that encompass more than one gestational week. The outcome of delivery, category Z37, should be included on all maternal delivery records. It is always a secondary code. Codes in category Z37 should not be used on the newborn record. Z codes for family planning (contraceptive) or procreative management and counseling should be included on an obstetric record either during the pregnancy or the postpartum stage, if applicable. Z codes/categories for obstetrical and reproductive services:

Z30 Encounter for contraceptive management

Z31 Encounter for procreative management

Z32.2 Encounter for childbirth instruction

Z32.3 Encounter for childcare instruction

Z33 Pregnant state

Z34 Encounter for supervision of normal pregnancy

Z36 Encounter for antenatal screening of mother

Z3A Weeks of gestation

Z37 Outcome of delivery

Z39 Encounter for maternal postpartum care and examination

Z76.81 Expectant mother prebirth pediatrician visit

12) Newborns and Infants

See Section I.C.16. Newborn (Perinatal) Guidelines, for further instruction on the use of these codes. Newborn Z codes/categories:

Z76.1 Encounter for health supervision and care of foundling

Z00.1- Encounter for routine child health examination

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

13) Routine and administrative examinations

The Z codes allow for the description of encounters for routine examinations, such as, a general check-up, or, examinations for administrative purposes, such as, a pre-employment physical. The codes are not to be used if the examination is for diagnosis of a suspected condition or for treatment purposes. In such cases the diagnosis code is used. During a routine exam, should a diagnosis or condition be discovered, it should be coded as an additional code. Pre-existing and chronic conditions and history codes may also be included as additional codes as long as the examination is for administrative purposes and not focused on any particular condition. Some of the codes for routine health examinations distinguish between "with" and "without" abnormal findings. Code assignment depends on the information that is known at the time the encounter is being coded. For example, if no abnormal findings were found during the examination, but the encounter is being coded before test results are back, it is acceptable to assign the code for "without abnormal findings." When assigning a code for "with abnormal findings," additional code(s) should be assigned to identify the specific abnormal finding(s). Pre-operative examination and pre-procedural laboratory examination Z codes are for use only in those situations when a patient is being cleared for a procedure or surgery and no treatment is given. The Z codes/categories for routine and administrative examinations:

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

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

Z02 Encounter for administrative examination. Except: Z02.9, Encounter for administrative examinations, unspecified

Z32.0- Encounter for pregnancy test

14) Miscellaneous Z codes

The miscellaneous Z codes capture a number of other health care encounters that do not fall into one of the other categories. Certain of these codes identify the reason for the encounter; others are for use as additional codes that provide useful information on circumstances that may affect a patient's care and treatment.

Prophylactic Organ Removal

For encounters specifically for prophylactic removal of an organ (such as prophylactic removal of breasts due to a genetic susceptibility to cancer or a family history of cancer), the principal or first-listed code should be a code from category Z40, Encounter for prophylactic surgery, followed by the appropriate codes to identify the associated risk factor (such as genetic susceptibility or family history). If the patient has a malignancy of one site and is having prophylactic removal at another site to prevent either a new primary malignancy or metastatic disease, a code for the malignancy should also be assigned in addition to a code from subcategory Z40.0, Encounter for prophylactic surgery for risk factors related to malignant neoplasms. A Z40.0 code should not be assigned if the patient is having organ removal for treatment of a malignancy, such as the removal of the testes for the treatment of prostate cancer. Miscellaneous Z codes/categories:

Z28 Immunization not carried out

Except: Z28.3, Underimmunization status

Z29 Encounter for other prophylactic measures
Z40 Encounter for prophylactic surgery
Z41 Encounter for procedures for purposes other than remedying health state

Except: Z41.9, Encounter for procedure for purposes other than remedying health state, unspecified

Z53 Persons encountering health services for specific procedures and treatment, not carried out
Z55 Problems related to education and literacy
Z56 Problems related to employment and unemployment
Z57 Occupational exposure to risk factors
Z58 Problems related to physical environment
Z59 Problems related to housing and economic circumstances
Z60 Problems related to social environment
Z62 Problems related to upbringing
Z63 Other problems related to primary support group, including family circumstances
Z64 Problems related to certain psychosocial circumstances
Z65 Problems related to other psychosocial circumstances
Z72 Problems related to lifestyle

Note: These codes should be assigned only when the documentation specifies that the patient has an associated problem

Z73 Problems related to life management difficulty
Z74 Problems related to care provider dependency

Except: Z74.01, Bed confinement status

Z75 Problems related to medical facilities and other health care
Z76.0 Encounter for issue of repeat prescription
Z76.3 Healthy person accompanying sick person
Z76.4 Other boarder to healthcare facility
Z76.5 Malingerer [conscious simulation]
Z91.1- Patient's noncompliance with medical treatment and regimen
Z91.83 Wandering in diseases classified elsewhere
Z91.89 Other specified personal risk factors, not elsewhere classified

15) Nonspecific Z codes

Certain Z codes are so non-specific, or potentially redundant with other codes in the classification, that there can be little justification for their use in the inpatient setting. Their use in the outpatient setting should be limited to those instances when there is no further documentation to permit more precise coding. Otherwise, any sign or symptom or any other reason for visit that is captured in another code should be used. Nonspecific Z codes/categories:

Z02.9 Encounter for administrative examinations, unspecified

Z04.9 Encounter for examination and observation for unspecified reason

Z13.9 Encounter for screening, unspecified

Z41.9 Encounter for procedure for purposes other than remedying health state, unspecified

Z52.9 Donor of unspecified organ or tissue

Z86.59 Personal history of other mental and behavioral disorders

Z88.9 Allergy status to unspecified drugs, medicaments and biological substances status

Z92.0 Personal history of contraception

16) Z Codes That May Only be Principal/First-Listed Diagnosis

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

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

Z31.83 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

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