PROTHROMBIN TIME DERIVED FIBRINOGEN DETERMINATION ON SYSMEX CA6000(TM)

Aim-To evaluate PT derived fibrinogen determinations with reference to the Clauss fibrinogen assay using a Sysmex CA-6000(TM) random access coagulation analyser. Methods-Samples were analysed from normal subjec ts (n = 20), patients with renal or liver dysfunction (n = 25), critic ally ill patients (n = 25), patients receiving oral anticoagulant trea tment (n = 50), and patients with a haemoglobinopathy (n = 127). Proth rombin times were performed using two thromboplastins: one derived fro m rabbit brain (Dade: Thromboplastin IS) and the other from recombinan t human tissue factor (Dade: Innovin). Fibrinogen was assayed by the C lauss method using a commercial kit (Dade: Fibrinogen). Results-The re lation between Clauss fibrinogen and PT derived fibrinogen was found t o be dependent on the patient's clinical group and source of the throm boplastin used. When the data from the above sample groups were pooled there was still a significant difference (p < 0.001) between Clauss f ibrinogen and PT derived fibrinogen, irrespective of thromboplastin us ed. Conclusions-It is unsafe to use the PT derived fibrinogen for pati ent monitoring owing to non-uniform variability in response to clinica l status and reagent employed; however, it may prove to be a useful sc reening test in a research environment for estimating fibrinogen level s among defined patient groups.