T86.91
BillableUnspecified transplanted organ and tissue rejection
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is T86.91 an HCC code?
No. T86.91 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
T86.91 is the ICD-10-CM diagnosis code for unspecified transplanted organ and tissue rejection. The patient's immune system is rejecting a transplanted organ or tissue, but the specific organ type is not identified. T86.91 sits in the ICD-10-CM chapter for injury, poisoning and certain other consequences of external causes (s00-t88), within the section covering complications of surgical and medical care, not elsewhere classified (t80-t88).
T86.91 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.
Attempt to identify the specific transplanted organ from the medical record and use a more specific code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for T86.91 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Attempt to identify the specific transplanted organ from the medical record and use a more specific code
- •Document whether rejection is hyperacute, acute, or chronic if available