Question 1

What is ICD-10 code Z91.119?

Accepted Answer

Z91.119 is the ICD-10-CM diagnosis code for Patient's noncompliance with dietary regimen due to unspecified reason. A patient is not following their prescribed diet, but the specific reason for this noncompliance is not documented or known. Z91.119 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. Z91.119 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Question 2

Is Z91.119 an HCC code?

Accepted Answer

No. Z91.119 is a billable ICD-10-CM code but does not map to any payment HCC category under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can still be reported on Medicare Advantage encounter data submissions, but it does not contribute to the beneficiary's Risk Adjustment Factor (RAF) score and therefore does not affect the risk-adjusted capitation payment to the plan. V28 reached 100% phase-in for payment year 2026.

Question 3

Is Z91.119 billable?

Accepted Answer

Yes. Z91.119 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. Z91.119 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Question 4

What is the V28 vs V24 difference for Z91.119?

Accepted Answer

Z91.119 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards Z91.119 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

Question 5

What should coders know when reporting Z91.119?

Accepted Answer

This is a default code used when the reason for dietary noncompliance cannot be determined or is not specified Encourage providers to document the specific reason when possible to allow for more precise coding

HCC Buddy Code Card

Z91.119

Is Z91.119 an HCC code?

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Open Z91.119 in the Interactive Encoder

Z91.119 ICD-10-CM Code: Patient's noncompliance with dietary regimen due to unspecified reason

HCC Buddy Code Card

Z91.119

Is Z91.119 an HCC code?

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Open Z91.119 in the Interactive Encoder