Z91.13 Patient's unintentional underdosing of medication regimen
The ICD-10-CM code for Patient's unintentional underdosing of medication regimen is Z91.13 (FY2026). It is a non-billable category code — select a more specific code below for claims.
Classification
- Section
- Z77-Z99: Persons with potential health hazards related to family and personal history and certain conditions influencing health status (Z77-Z99)
- Category Z91
- 87 codes (62 billable)
- FY2026 Status
- Stable since FY2024
Official Coding Guidelines
Use Z91.12-/Z91.13-/Z91.14-/Z91.A4- or Y63.6-Y63.9 with underdosingNoncompliance (Z91.12-, Z91.13-, Z91.14- and Z91.A4-) or complication of care (Y63.6-Y63.9) codes are to be used with an underdosing code to indicate intent, if known.
Unlabeled Z code list + cross-reference to I.B.14Z76.3 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.A- Caregiver’s noncompliance with patient’s medical treatment and regimen Z91.B Personal risk factor of exposure to diethylstilbestrol Z91.83 Wandering in diseases classified elsewhere Z91.84- Oral health risk factors Z91.89 Other specified personal risk factors, not elsewhere classified See Section I.B.14. for Z55-Z65 Persons with potential health hazards related to socioeconomic and psychosocial circumstances, documentation by clinicians other than the patient’s provider
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026