T86.850
BillableIntestine transplant rejection
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is T86.850 an HCC code?
Yes. T86.850 maps to Intestine Transplant Status/Complications under the CMS-HCC V28 risk adjustment model (and Major Organ Transplant or Replacement Status under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for T86.850
For T86.850 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed T86.850 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
T86.850 is the ICD-10-CM diagnosis code for intestine transplant rejection. The recipient's immune system attacks and rejects a transplanted intestine, causing it to fail. T86.850 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).
Under the CMS-HCC V28 risk adjustment model, T86.850 maps to Intestine Transplant Status/Complications (HCC 77) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, T86.850 maps to Major Organ Transplant or Replacement Status (HCC 186) with a community, non-dual, aged base RAF weight of 0.910. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
This code specifically indicates rejection of an intestinal transplant, which is an immune-mediated response. Because T86.850 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for T86.850 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code specifically indicates rejection of an intestinal transplant, which is an immune-mediated response
- •Document the timeframe of rejection (acute vs. chronic) if available, as this may affect clinical management
Clinical Significance
Intestinal transplant rejection represents an immunologic attack on the transplanted bowel, potentially leading to graft loss and life-threatening complications. This diagnosis requires immediate immunosuppressive therapy adjustment and intensive monitoring.
Documentation Requirements
- ✓Documentation of intestinal transplant procedure with date
- ✓Histologic evidence of rejection from biopsy
- ✓Clinical symptoms of rejection (diarrhea, abdominal pain, fever)
- ✓Laboratory evidence supporting rejection (inflammatory markers, absorption studies)
- ✓Immunosuppressive medication history and levels
- ✓Endoscopic findings if applicable
- ✓Provider assessment confirming rejection diagnosis
- ✓Treatment plan for rejection management
Commonly Confused Codes
- •T86.851 — intestine transplant failure (rejection vs functional failure)
- •T86.852 — intestine transplant infection (immunologic vs infectious complication)
- •K59.1 — diarrhea (transplant rejection vs other causes)
- •Z94.82 — intestine transplant status (rejection vs stable status)
- •T86.858 — other intestine transplant complications (rejection vs other complications)