Hematologic Considerations in Kidney Transplantation: Core Curriculum 2025.

Hematologic abnormalities including both cytopenias and cytoses are the rule rather than the exception in the first year after kidney transplantation, yet many are benign reflections of immunosuppression, infection prophylaxis, or residual chronic kidney disease. In this Core Curriculum, we distill the evidence on the disorders clinicians encounter most often, cytopenias including neutropenia, lymphopenia, anemia, thrombocytopenia, and thrombotic microangiopathy, as well as cytoses including eosinophilia, lymphocytosis, erythrocytosis, and thrombocytosis. Each is framed by typical timing, dominant mechanisms, key drugs or pathogens, and decision making checkpoints. Five real-world cases illustrate how to differentiate harmless findings from conditions that mandate prompt action, such as drug-induced marrow suppression, cytomegalovirus reactivation, antibiotic-triggered eosinophilia, posttransplant erythrocytosis, and thrombotic microangiopathy. Adopting this problem-oriented approach can reduce unnecessary drug interruptions, target hematology referrals, and preserve both patient safety and allograft longevity.