Background: The Clot Signature Analyzer (CSA) was designed to assess global hemostasis as a screening assay using non‐anticoagulated whole blood. Three different measurements are produced by the instrument: platelet hemostasis time (PHT), clot time (CT), and collagen‐induced thrombus formation (CITF). Objectives: The purpose of the present study was to determine normal ranges for these measurements and assess the performance of the CSA in patients with well‐characterized hemostatic disorders and in normal subjects. Patients and methods: Four institutions participated in the study. Each established their own normal reference ranges. Patients with well‐characterized hemostatic disorders and concurrent normal controls were subsequently examined. Results: Normal ranges between institutions were similar although statistically different. One hundred and eight patients were examined: 46 individuals with von Willebrand disease (VWD) (type 1, 26; type 2A, 11; type 2B, six; type 3, three); 38 patients with a coagulation factor deficiency; 13 individuals with platelet function defects; 10 patients taking warfarin; and one individual on low‐molecular‐weight heparin. Of these patients, 89% had at least one abnormality by CSA: 42/46 VWD patients, 35/38 coagulation protein defect patients, 9/13 patients with platelet function defects, 9/10 patients on warfarin and 1/1 patient on low‐molecular‐weight heparin. Of 116 normal subjects, 103 (89%) fell within the centers' normal range. These data suggest that the CSA has a good sensitivity for bleeding disorders.
