ICD-10-CM
ICD-10 code for Underdosing intentional NEC: Z91.128
The ICD-10-CM index points "Underdosing intentional NEC" to Z91.128, Patient's intentional underdosing of medication regimen for other reason. Z91.128 is a billable code.
Source: CDC ICD-10-CM FY2027 Alphabetic Index file dated June 16, 2026. Publisher page
Run it in Rivvi
Check every code on your export
Upload a claims or problem-list export. Rivvi flags codes that are not billable, replaced, or unspecified when a specific code exists.
Check my exportFree to start. Opens Rivvi, the AI workspace for healthcare teams.
Index subterms
A header groups codes and is not billed. A billable code is one you can report.
More specific codes in Z91
A header groups codes and is not billed. A billable code is one you can report. Listed second marks a billable manifestation code (its CDC title says it is "classified elsewhere"): code the underlying disease or condition first, then this code.
- Z91Personal risk factors, not elsewhere classifiedHeader
- Z91.0Allergy status, other than to drugs and biological substancesHeader
- Z91.01Food allergy statusHeader
- Z91.02Food additives allergy statusBillable
- Z91.03Insect allergy statusHeader
- Z91.04Nonmedicinal substance allergy statusHeader
- Z91.09Other allergy status, other than to drugs and biological substancesBillable
- Z91.1Patient's noncompliance with medical treatment and regimenHeader
- Z91.11Patient's noncompliance with dietary regimenHeader
- Z91.12Patient's intentional underdosing of medication regimenHeader
- Z91.13Patient's unintentional underdosing of medication regimenHeader
- Z91.14Patient's other noncompliance with medication regimenHeader
- Z91.15Patient's noncompliance with renal dialysisHeader
- Z91.19Patient's noncompliance with other medical treatment and regimenHeader
- Z91.4Personal history of psychological trauma, not elsewhere classifiedHeader
- Z91.41Personal history of adult abuseHeader
- Z91.42Personal history of forced labor or sexual exploitationBillable
- Z91.49Other personal history of psychological trauma, not elsewhere classifiedBillable
- Z91.5Personal history of self-harmHeader
- Z91.51Personal history of suicidal behaviorBillable
- Z91.52Personal history of nonsuicidal self-harmBillable
- Z91.8Other specified personal risk factors, not elsewhere classifiedHeader
- Z91.81History of fallingBillable
- Z91.82Personal history of military deploymentBillable
- Z91.83Wandering in diseases classified elsewhereListed second
- Z91.84Oral health risk factorsHeader
- Z91.85Personal history of military serviceBillable
- Z91.89Other specified personal risk factors, not elsewhere classifiedBillable
- Z91.ACaregiver's noncompliance with patient's medical treatment and regimenHeader
- Z91.A1Caregiver's noncompliance with patient's dietary regimenHeader
- Z91.A2Caregiver's intentional underdosing of patient's medication regimenHeader
- Z91.A3Caregiver's unintentional underdosing of patient's medication regimenBillable
- Z91.A4Caregiver's other noncompliance with patient's medication regimenHeader
- Z91.A5Caregiver's noncompliance with patient's renal dialysisHeader
- Z91.A9Caregiver's noncompliance with patient's other medical treatment and regimenHeader
- Z91.BPersonal risk factor of exposure to diethylstilbestrolBillable
Code first
The CDC tabular list says to report the code named here before this one.
From Z91.12. A note on a category applies to every code under it.
Code first underdosing of medication (T36-T50) with fifth or sixth character 6
Code also
The CDC tabular list says a second code may be needed with this one. The note does not set which is listed first.
From Z91.1. A note on a category applies to every code under it.
Code also, if applicable, to identify underdosing of specific drug (T36-T50 with final character 6)
Excludes2
Related conditions
Related pages
- Z91.128 code detailsNotes, nearby codes, CMS-HCC group
- Category Z91Every code under it
- Chapter 21Factors influencing health status
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Underdosing intentional NEC?
The ICD-10-CM index points "Underdosing intentional NEC" to Z91.128, Patient's intentional underdosing of medication regimen for other reason. Z91.128 is a billable code.
Is Z91.128 billable?
Yes. Z91.128 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What documentation notes apply to Z91.128?
The CDC tabular list gives 6 Excludes2 notes (may be coded together when both are documented) for Z91.128 and the categories above it. They are listed on this page.
What chapter is Z91.128 in?
Chapter 21. Factors influencing health status.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.