An antithrombin III assay based on factor Xa inhibition provides a more reliable test to identify congenital antithrombin III deficiency than an assay based on thrombin inhibition - Demers, C; Henderson, P; Blajchman, MA; Wells, MJ; Mitchell, L; Johnston, M; Ofosu, FA; Fernandez, RF; Andrew, M; Hirsh, J (Thromb Haemostas, 1993)