Determinazione degli anticoagulanti orali diretti in regime di urgenza. [Determination of direct oral anticoagulants in urgency]

Background.: The direct oral anticoagulants (DOAC) dabigatran, rivaroxaban and apixaban are alternative drugs to warfarin, that have changed the management of the patients with thromboembolic disorders in a few years. Their most appealing features are fixed-dose administration and no need for routine monitoring. This does not mean that their determination is not needed in some cases, mainly in emergency. In this work we report the pathway taken for the determination of these drugs in emergency, in order to optimize and reduce the reporting time of the plasma value of DOAC. Methods.: Dabigatran was dosed by the diluted thrombin time (DTT) using the BC Thrombin reagent (Siemens, Milano, Italia). For rivaroxaban and apixaban the Biophen DIXa anti-Xa assay was used (Hyphen BioMed, Neuville-sur-Oise, France). Plasma calibrators and controls were provided by Hyphen BioMed. All assays were performed on the BCS XP coagulometer (Siemens). Results.: By April 2016 the Clinical Pathology Laboratory had introduced the dosage of DOAC both in routine and in emergency, focusing particular attention to the optimization of the emergency pathway. The pathway was described in a protocol that has been shared with physicians of both the polyclinic and the South-East extensive area of Tuscany, being our the only laboratory performing this type of assays. In summary, polyclinic departments and, even more stringently, hospitals in the extensive area need to call before sending the sample by specifying the type of drug, whether the patient is taking other anticoagulants and, when possible, the time interval between last administration and blood sampling. In the study period, 22 determinations of DOAC were performed: 11 for dabigatran, 3 for rivaroxaban and 8 for apixaban. Urgent requests accounted for 68% and routine for 32%, being the Emergency the most frequent requesting department, followed by Surgical and Medicine departments. The values obtained confirmed the wide range that can be obtained for these drugs, which are affected by the time interval between drug assumption and blood sampling, and by the large inter-individual variability. Conclusions.: The pathway optimization has enabled the value of DOAC to be released within 30 minutes from the arrival of the patient’s tube in the laboratory. Providing a 24 h quantitative determination of DOAC in less than an hour has proved useful in the management of critically ill patients being treated with these drugs. © 2017, Società Italiana di Patologia Clinica e Medicina di Laboratorio.