A36.1
BillableNasopharyngeal diphtheria
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A36.1 an HCC code?
No. A36.1 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
A36.1 is the ICD-10-CM diagnosis code for nasopharyngeal diphtheria. Diphtheria is a serious bacterial infection that affects the nose and throat area, causing inflammation and a thick membrane to form that can block breathing. This specific type occurs when the infection is localized to the nasopharynx (the upper part of the throat behind the nose). A36.1 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other bacterial diseases (a30-a49).
A36.1 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.
Verify documentation specifies nasopharyngeal involvement rather than other diphtheria sites (respiratory, cutaneous, or unspecified) as each has a different code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A36.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation specifies nasopharyngeal involvement rather than other diphtheria sites (respiratory, cutaneous, or unspecified) as each has a different code
- •Diphtheria is a reportable disease in most jurisdictions; ensure proper public health reporting is completed alongside coding