Billable / Specific Code
ICD-10-CM Z91.128 is the diagnosis code for Patient's intentional underdosing of medication regimen for other reason. This code falls under the section "Persons with potential health hazards related to family and personal history and certain conditions influencing health status" within Chapter 21 — Factors influencing health status and contact with health services (Z00-Z99). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.
Understanding where Z91.128 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, Z91.128 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
Z91.128 is the ICD-10-CM diagnosis code for "Patient's intentional underdosing of medication regimen for other reason". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of Z91.128 is Z91.12 ("Patient's intentional underdosing of medication regimen"). Z91.128 provides a more specific classification within this category.
Z91.128 is located in Section Z77-Z99 — "Persons with potential health hazards related to family and personal history and certain conditions influencing health status" within Chapter 21 of the ICD-10-CM Tabular List.
Use Z91.128 when the patients documented diagnosis matches "Patient's intentional underdosing of medication regimen for other reason" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Patient's intentional underdosing of medication regimen for other reason is Z91.128.
Yes, Z91.128 can be used as a primary diagnosis code since it is billable and specific.
Z91.128 is in Chapter 21 of the ICD-10-CM Tabular List.
Yes, Z91.128 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.