Urgessa,Fekadu(MSc,PhD Candidate)Hordofa,Moges(MSc)Bisrat,Elias(MSc)Genene,Amanuel2026-06-222026-06-222025-06https://etd.aau.edu.et/handle/123456789/8506Background: Many cancer patients, especially those with blood cancers like acute Leukemia, face a serious risk of bleeding, which can lead to death. About 52% of these patients have bleeding complications. The extent of optimal platelet transfusion response is not well known, and the predictors of transfusion effectiveness remain poorly understood. Therefore, assessing the factors influencing transfusion outcomes is essential, yet research on this remains limited. Objective: To assess of Platelet Count Changes in Adult Acute Leukemia Patients Receiving Platelet Transfusions at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia. Methods: A facility-based cross-sectional study was conducted from December 2024 to May 2025 at Tikur Anbessa Specialized Hospital involving 174 adult acute leukemia patients receiving platelet transfusions. Informed consent was obtained from all participants. Blood samples were collected pre-transfusion, at 1 hour, and 24 hours post-transfusion. Corrected count increment (CCI) was calculated by subtracting pretransfusion platelet counts from post-transfusion counts, multiplying by the patient’s body surface area (m²), and dividing by the total number of platelets transfused. An optimal response was defined as a CCI ≥ 7.5 × 10⁹/L at 1 hour and ≥ 4.5× 10⁹/L at 24 hours. Logistic regression was used to identify predictors of CCI. Result: Of the 174 patients, the mean age was 31.45 years, and 67.2% were male. Acute lymphoblastic leukemia was more common (59.2%) than acute myeloid leukemia. Overall, 81.7% and 68.6% of transfusions resulted in optimal CCI at 1 hour and 24 hours, respectively. In multivariable analysis, not taking medication was significantly negatively associated with achieving optimal CCI at 1 hour (AOR=0.54, P=0.022). Additionally, new infection (AOR= 0.1248, P=0.003) were negatively associated with optimal 1-hour CCI. An increase in the number of transfused platelet units was significantly associated with decreased odds of achieving an optimal CCI at 24 hours (AOR = 0.027, p = 0.045 as the AOR was less than 1. Conclusion: Most patients achieved optimal CCI post-transfusion. The unit of transfused platelets was inversely associated with optimal CCI at 24 hours. Infection and not taking medication were inversely associated with optimal 1-hour CCI. Future longitudinal studies using incorporating immunological assessments are recommended to understand predictors of optimal platelet increment changeen-USPlatlet CountAcute LukemiaPlatlet transfusionThesis