ORIGINAL ARTICLESThe effects of unfractionated heparin, low molecular weight heparin and danaparoid on the thromboelastogram (TEG): an in-vitro comparison of standard and heparinase-modified TEGs with conventional coagulation assaysCoppell, Jason Aa; Thalheimer, Ulrichb; Zambruni, Andreab; Triantos, Christos Kb; Riddell, Anne Fa; Burroughs, Andrew Kb; Perry, David JaAuthor Information aHaemophilia Centre and Haemostasis Unit bLiver Transplantation and Hepatobiliary Medicine, Royal Free Hospital, London, UK Received 21 July, 2005 Accepted 21 November, 2005 Correspondence and requests for reprints to Dr J.A. Coppell, Haemophilia Centre and Haemostasis Unit, Royal Free Hospital, Pond Street, London NW3 2QG, UK Fax: +44 20 7472 6759; e-mail: [email protected] Blood Coagulation & Fibrinolysis: March 2006 - Volume 17 - Issue 2 - p 97-104 doi: 10.1097/01.mbc.0000203859.62739.25 Buy Metrics Abstract To investigate the effects of unfractionated heparin (UFH), low molecular weight heparin (LMWH) and danaparoid (DPD) added to whole blood in vitro on standard and heparinase-modified thromboelastogram (TEG) parameters compared with conventional assays of coagulation. The effects of UFH, LMWH and DPD on standard TEG parameters were compared with the prothrombin time, activated partial thromboplastin time, thrombin time and anti-activated factor X (anti-FXa) activity, at concentrations of these anticoagulants ranging from 0.025 to 1 U/ml. In the second part of the study, the effects of very low concentrations (0.005–0.05 U/ml) of UFH, LMWH and DPD on the difference between standard and heparinase-modified TEG parameters were compared with the prothrombin time, activated partial thromboplastin time, thrombin time and anti-FXa activity. Standard TEG parameters were outside the reference range at lower concentrations of UFH, LMWH and DPD than most conventional coagulation assays were able to detect. Only anti-FXa activity was more sensitive to the presence of these anticoagulants than the standard TEG alone. The lowest concentration of UFH, LMWH and DPD used in this study (0.005 U/ml) caused significant differences between the standard and heparinase-modified α-angles of the TEG. In addition, the difference between standard and heparinase-modified TEG parameters distinguished between low concentrations (0.005–0.05 U/ml) of UFH with greater sensitivity than anti-FXa activity, but were less sensitive to LMWH and DPD. The standard TEG is more sensitive to UFH, LMWH and DPD than most conventional coagulation tests, with the exception of anti-FXa activity. Calculation of the difference between standard and heparinase-modified TEG parameters greatly increases the sensitivity of the assay for the effects of these anticoagulants, and is more sensitive to very low quantities of UFH than anti-FXa activity. © 2006 Lippincott Williams & Wilkins, Inc.