Z91.13 – Patient's unintentional underdosing of medication regimen

ICD-10-CM 2027 diagnosis code · Persons with potential health hazards related to family and personal history and certain conditions influencing health status

Non-billable header

ICD-10-CM code Z91.13
Code
Z91.13 (claims format: Z9113)
Description
Patient's unintentional underdosing of medication regimen
Billable
No – use a more specific code below
Valid for
Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter
21. Factors influencing health status and contact with health services (Z00-Z99)
Block
Z77-Z99 Persons with potential health hazards related to family and personal history and certain conditions influencing health status
Parent codes
Z91 › Z91.1

Billable codes under Z91.13

Z91.13 is a header code and cannot be used on claims. Choose the most specific code:

Notes for Z91.13

Code first:
  • underdosing of medication (T36-T50) with fifth or sixth character 6

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

Z91 – Personal risk factors, not elsewhere classified

Excludes2 (not included here):
  • 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-)

Z91.1 – Patient's noncompliance with medical treatment and regimen

Excludes2 (not included here):
  • caregiver noncompliance with patient's medical treatment and regimen (Z91.A-)
Code also:
  • , if applicable, to identify underdosing of specific drug (T36-T50 with final character 6)

Block Z77-Z99

Code also:
  • any follow-up examination (Z08-Z09)

Related codes in Z91.1

Frequently asked questions

What is ICD-10 code Z91.13?

Z91.13 is the ICD-10-CM code for patient's unintentional underdosing of medication regimen, in the block Z77-Z99 (Persons with potential health hazards related to family and personal history and certain conditions influencing health status).

Is Z91.13 a billable code?

No. Z91.13 is a header code with more specific child codes; report one of the billable codes listed above.

What category does Z91.13 belong to?

It belongs to category Z91 – Personal risk factors, not elsewhere classified.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.