Question 1

What is ICD-10 code R42?

Accepted Answer

R42 is the ICD-10-CM diagnosis code for dizziness and giddiness. A spinning sensation or feeling of lightheadedness and unsteadiness, commonly called vertigo or dizziness. R42 sits in the ICD-10-CM chapter for symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (r00-r99), within the section covering symptoms and signs involving cognition, perception, emotional state and behavior (r40-r46).

R42 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.

Distinguish between vertigo (spinning sensation) and presyncope (feeling faint) for accurate coding.

Question 2

Is R42 an HCC code?

Accepted Answer

No. R42 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 R42 billable?

Accepted Answer

Yes. R42 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. R42 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 R42?

Accepted Answer

R42 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 R42 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 R42?

Accepted Answer

Distinguish between vertigo (spinning sensation) and presyncope (feeling faint) for accurate coding Document associated symptoms like nausea, hearing loss, or tinnitus to help identify underlying cause

R42

Is R42 an HCC code?

What This Code Means

Coding Tips

Excludes 1 — Do NOT code together

Code Hierarchy

Open R42 in the Interactive Encoder