Reduction of preanalytical errors due to in vitro activation of coagulation

Statistically significant errors due to activation of coagulation may result from the blood sampling procedure. In order to establish the magnitude of errors, blood sample aliquots were drawn in triplicate from one venipuncture. A procedure is described for discrimination of inappropriate analytical results in 162 subjects. Estimated percentages of insufficient duplicate results amounted to 36% for thrombin-antithrombin complexes, to 5% for prothrombin fragment 1+2, to 2% for fibrinogen degradation products and to 4% for fibrin degradation products. It is concluded that the overall reliability of results for coagulation analytes can be considerably improved by drawing blood samples in triplicate and subsequent rejection of samples with inappropriate reproducibility for thrombin-antithrombin. Routine parameters like prothrombin time or activated partial thromboplastin time in normal conditions are not susceptible for the phenomenon of coagulation activation.