Normal hemostasis is the result of a complex interaction between the vessel wall, platelets and coagulation proteins and their inhibitors. Abnormalities of hemostasis can be demonstrated and defined by a battery of screening tests and assays. Dr. Karpatkin is the director of the Special Hematology Laboratory at Bellevue Hospital which provides this testing for patients at Bellevue, Tisch and other hospitals in the New York City Health and Hospitals Corporation. Dr. Karpatkin?s research is directed at developing methods and modifying existing methods to improve diagnostic capability. Recently the laboratory has modified the fibrinogen assay by creating and validating new software in order to increase the accuracy of the assay in patients with fibrinogen levels below 80mg/dl. Currently the lab is engaged in refining tests for lupus anticoagulants to determine the most economic and efficient methodology and to try to discriminate between "harmless" lupus anticoagulants and those likely to be associated with thrombosis. The very large number of patient samples sent to the lab provides a wealth of material to pilot methodology and test algorithms.