Evaluation of the main coagulation tests in the presence of hemolysis in healthy subjects and patients on oral anticoagulant therapy

Introduction: Our study was designed to evaluate, on healthy subjects and patients on oral anticoagulant therapy vitamin K antagonist (OAT-vka), the possible interference caused by hemolysis on the main coagulation tests. Methods: To obtain hemolyzed samples, two methods were used: heat shock and mechanical system. The coagulation tests on hemolyzed samples were performed employing optical automated analyser BCSxp (Siemens Healthcare (R)). Moreover, the prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests were also carried out manually using an electromechanical device (KC4 - Amelung). Results: The PT test, on healthy subjects, in case of moderate hemolysis can be performed without significant interference on automatic instrument. On manual instrument, the PT test can be performed even in case of marked hemolysis. For patients on OAT-vka, the PT test in case of marked hemolysis can be performed both on automatic and manual instrument. For the aPTT test, it can be carried out manually, because also in case of marked hemolysis a statistically significant difference was not observed. For the fibrinogen test, a dramatic concentration decrease was already clear for weak hemolysis. A decreased function on antithrombin test was statistically significant for mild-moderate hemolysis. The D-dimer test showed increased values for mild hemolysis. Conclusions: The rejection of hemolyzed sample and/or the request of a second sample are not always the proper attitudes to take for performing clotting tests. The rational management of the hemolyzed samples decreases the employment of both nursing and technical staff significantly, the turnaround time and, consequently, does not lead to additional costs for each patient involved.