10ICD Code Hub

Z91.13

Header — not billable

Patient's unintentional underdosing of medication regimen

The ICD-10 code for patient's unintentional underdosing of medication regimen is Z91.13.

Z91.13 is a non-billable header code. It groups related conditions but cannot be used on its own for reimbursement — select one of the 2 more specific codes below.

Clinical notes

Code first

This code represents a manifestation of an underlying disease. Coding convention requires the underlying (etiology) code to be sequenced first, with this code listed second.

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

Documentation support

General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.

Child codes under Z91.13

Related codes in this category