Question 1

What is ICD-10 code O43.199?

Accepted Answer

O43.199 is the ICD-10-CM diagnosis code for other malformation of placenta, unspecified trimester. The placenta has an abnormal structure or formation other than velamentous insertion or accreta, but the specific trimester is not documented. O43.199 sits in the ICD-10-CM chapter for pregnancy, childbirth and the puerperium (o00-o9a), within the section covering maternal care related to the fetus and amniotic cavity and possible delivery problems (o30-o48).

O43.199 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 only when trimester information is unavailable or unclear.

Question 2

Is O43.199 an HCC code?

Accepted Answer

No. O43.199 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 O43.199 billable?

Accepted Answer

Yes. O43.199 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. O43.199 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 O43.199?

Accepted Answer

O43.199 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 O43.199 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 O43.199?

Accepted Answer

Use only when trimester information is unavailable or unclear Attempt to query provider for trimester specification to assign more specific code

O43.199

Is O43.199 an HCC code?

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Open O43.199 in the Interactive Encoder