title: Sensitivity of the thrombin clotting time and activated partial thromboplastin time to low level of antithrombin III during heparin therapy.
abstract: The thrombin clotting time (TCT) has been used at our institution, along with the activated partial thromboplastin time (aPTT), for monitoring heparin therapy. We have observed that, in some patients, a discrepancy develops between the heparin levels predicted by the TCT and the aPTT with the TCT consistently predicting a lower heparin level than the aPTT. An inverse relationship was noted between the functional antithrombin III (AT-III) level and the magnitude of this discrepancy.
authors.affiliation: Division of Hematology and Oncology, St. Joseph's Health Centre, University of Western Ontario, London, Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Delorme
authors.forename: M J
authors.initials: MJ
authors.lastname: Inwood
authors.forename: B
authors.initials: B
authors.lastname: O'Keefe
mesh_terms: D000990:Antithrombin III / Q000494:pharmacology*; D020152:Antithrombin III Deficiency; D004305:Dose-Response Relationship, Drug; D006493:Heparin / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008991:Monitoring, Physiologic; D010314:Partial Thromboplastin Time; D011237:Predictive Value of Tests; D013918:Thrombin Time
chemical_list: D000990:Antithrombin III; D006493:Heparin