Question 1

What is ICD-10 code O21.8?

Accepted Answer

O21.8 is the ICD-10-CM diagnosis code for other vomiting complicating pregnancy. Other types of nausea and vomiting during pregnancy that do not fit into the standard categories of hyperemesis gravidarum or late vomiting. O21.8 sits in the ICD-10-CM chapter for pregnancy, childbirth and the puerperium (o00-o9a), within the section covering other maternal disorders predominantly related to pregnancy (o20-o29).

O21.8 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.

Use this code for atypical vomiting presentations in pregnancy; document the specific characteristics.

Question 2

Is O21.8 an HCC code?

Accepted Answer

No. O21.8 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 O21.8 billable?

Accepted Answer

Yes. O21.8 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. O21.8 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 O21.8?

Accepted Answer

O21.8 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 O21.8 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 O21.8?

Accepted Answer

Use this code for atypical vomiting presentations in pregnancy; document the specific characteristics Ensure the vomiting is pregnancy-related and not due to other gastrointestinal conditions

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O21.8

Is O21.8 an HCC code?

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O21.8 ICD-10-CM Code: Other vomiting complicating pregnancy

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O21.8

Is O21.8 an HCC code?

What This Code Means

Coding Tips

Use Additional Code

Child Codes

Code Hierarchy

Work O21.8 in HCC Buddy