The Division of Hematopathology combines the diagnostic aspects of laboratory hematology and coagulation, bone marrow interpretation and flow cytometric analysis. The overall Division of Hematopathology is directed by Dr. Frederick Racke. Dr. Racke also oversees the hematopathology fellowship program. In addition to his clinical activities, Dr. Racke is a clinician scientist with focused work in the area of signal transduction and megakaryocytic differentiation and thrombopoiesis. He also continues to lead the pathology leukemia cadre of the Cancer and Luekemia Group B (CALGB), participating in correlative science related to the refinement of the diagnosis of leukemia and development of clinical assays for prognostic markers in acute myeloid leukemia. Within the Division, the coagulation laboratory is under the direction of Dr. Haifeng Wu and the flow cytometry laboratory is under the direction of Dr. Gerard Lozanski. Another member of the division, Dr. Weiqiang Zhao, in addition to his involvement in the clinical hematopathology activities, is involved in development of clinical and research molecular tests as part of the Pathology Core Facility Laboratory. Also participating in the clinical activities of the division are Dr. Arwa Shana’ah, who has also recently been named director of the pathology residency program at OSU, and Dr. Amy Gewirtz, who in addition to her divisional activities, is the Director of Clinical Laboratories at OSU and Vice Chair of Clinical Pathology. Dr. Wu continues to advance our knowledge in the clinical diagnosis, treatment and outcomes measurement of thrombotic thrombocytopenic purpura with his performance of assays for ADAMTS 13 activity, antigen, antibody and antibody activity assays. ADAMTS13 activity and inhibitor titer assays have been implemented as the standard clinical tests at OSUMC. The laboratory has also developed and optimized a procedure for vWF multimer analysis. Dr. Wu’s research interests also includes the area of proteomics as relates to plasma microparticles, the cell vesicles/fragments that are derived from injured or necrotic cells as a source of biomarkers for early diagnosis or prediction of autoimmune disorders or malignancy. The Flow Cytometry Laboratory, under the direction of Dr. Gerard Lozanski, continues to experience marked increase in volume of clinical cases over the past year. The laboratory has expanded its detection of minimal residual disease to include not only CLL but also ALL. Recently an extensive battery to allow for the detailed evaluation of the immune status of patients treated with bone marrow transplant, solid organ transplant or suffering from immunosuppression or autoimmune disorders has been developed. This panel determines percentage and absolute number of naïve, memory, Th1, Th2 and regulator T cells and reports early, mid and late activation status of B, T and NK cells. These increases emphasize the laboratory dual mission of an excellent Clinical Diagnostic Flow Laboratory providing immunophenotypic data used for diagnostic purposes and the emerging role of an innovative Clinical Academic Flow Laboratory actively participating in translational research and supporting individual investigators and organizations such as (CALGB), Eastern Cooperative Oncology Group (ECOG) and several biotechnology/pharmacologic companies in their mission to study and treat hematopoietic malignancies.