R79.81
BillableAbnormal blood-gas level
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is R79.81 an HCC code?
No. R79.81 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
R79.81 is the ICD-10-CM diagnosis code for abnormal blood-gas level. Blood gas test showing abnormal levels of oxygen, carbon dioxide, or acid-base balance in the blood. R79.81 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 abnormal findings on examination of blood, without diagnosis (r70-r79).
R79.81 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.
Always document the specific abnormality (hypoxemia, hypercapnia, acidosis, alkalosis) and the clinical context (respiratory vs. metabolic cause).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for R79.81 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always document the specific abnormality (hypoxemia, hypercapnia, acidosis, alkalosis) and the clinical context (respiratory vs. metabolic cause)
- •This is often an acute finding requiring immediate clinical intervention; correlate with respiratory status and vital signs