Patient's unintentional underdosing of medication regimen

• Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
• (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
• (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.

any follow-up examination (Z08-Z09)

• contact with and (suspected) exposures hazardous to health (Z77.-)
• exposure to pollution and other problems related to physical environment (Z77.1-)
• female genital mutilation status (N90.81-)
• occupational exposure to risk factors (Z57.-)
• personal history of physical injury and trauma (Z87.81, Z87.82-)

caregiver noncompliance with patient's medical treatment and regimen (Z91.A-)

, if applicable, to identify underdosing of specific drug (T36-T50 with final character 6)