T86.00
BillableUnspecified complication of bone marrow transplant
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is T86.00 an HCC code?
Yes. T86.00 maps to Graft-Versus-Host Disease and Stem Cell Transplant 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 T86.00
For T86.00 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 T86.00 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
T86.00 is the ICD-10-CM diagnosis code for unspecified complication of bone marrow transplant. A complication following a bone marrow transplant that is not further specified, such as graft-versus-host disease or other transplant-related problems. T86.00 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, T86.00 maps to Graft-Versus-Host Disease and Stem Cell Transplant Complications (HCC 454) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, T86.00 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.
Use this code only when the specific type of complication is not documented; attempt to obtain more specific documentation. Because T86.00 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 T86.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the specific type of complication is not documented; attempt to obtain more specific documentation
- •Requires a seventh character to indicate the episode of care (A, D, or S)
Clinical Significance
This indicates a complication following bone marrow transplant that requires ongoing monitoring and treatment, reflecting the complex immunosuppressed state and high risk for serious adverse events. These patients require specialized hematologic care and frequent monitoring for graft-versus-host disease, infection, and other transplant-related complications.
Documentation Requirements
- ✓History of bone marrow or stem cell transplant
- ✓Type of complication (if known)
- ✓Date of original transplant procedure
- ✓Current symptoms or manifestations
- ✓Treatment being provided for complication
- ✓Immunosuppressive medications
- ✓Laboratory values supporting complication
- ✓Impact on graft function or patient status