Question 1

What is ICD-10 code Z57.31?

Accepted Answer

Z57.31 is the ICD-10-CM diagnosis code for occupational exposure to environmental tobacco smoke. Exposure to secondhand smoke in the workplace environment. Z57.31 sits in the ICD-10-CM chapter for factors influencing health status and contact with health services (z00-z99), within the section covering persons with potential health hazards related to socioeconomic and psychosocial circumstances (z55-z65).

Z57.31 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Document the frequency and duration of environmental tobacco smoke exposure.

Question 2

Is Z57.31 an HCC code?

Accepted Answer

No. Z57.31 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 Z57.31 billable?

Accepted Answer

Yes. Z57.31 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. Z57.31 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 Z57.31?

Accepted Answer

Z57.31 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 community model rewards Z57.31 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

Question 5

What should coders know when reporting Z57.31?

Accepted Answer

Document the frequency and duration of environmental tobacco smoke exposure This code is useful for occupational health assessments and counseling related to smoke-free workplace initiatives

HCC Buddy Code Card

Z57.31

Is Z57.31 an HCC code?

Get the V28 RAF + MEAT cheat sheet

What This Code Means

Coding Tips

Excludes 2, Not included here, may code separately

Child Codes

Code Hierarchy

Work Z57.31 in HCC Buddy

Z57.31 ICD-10-CM Code: Occupational exposure to environmental tobacco smoke

HCC Buddy Code Card

Z57.31

Is Z57.31 an HCC code?

Get the V28 RAF + MEAT cheat sheet

What This Code Means

Coding Tips

Excludes 2, Not included here, may code separately

Child Codes

Code Hierarchy

Work Z57.31 in HCC Buddy