<br>Introduction: D-dimer is a product of stabilized fibrin degradation under the influence of plasmin. Evaluation of D-dimer concentration is crucial in exclusion of thromboembolism as well as in monitoring of coagulation and fibrinolysis processes in affected patients. Concentration of D-dimer corresponds with dynamics of clot formation and degradation in vessels.</br> <br>Aim: The aim of the study was to evaluate interchangeability of different analysers: ACL TOP 500 CTS, ACL TOP 700 CTS and VIDAS 3 in D-dimer assessment.</br> <br>Material and methods: Study included D-dimer measurements in 4476 patients. There were statistically significant differences in D-dimer concentration obtained with reference ELFA method and immunoturbidymetric method, both in women and men groups.</br> <br>Results: There were also significant differences in D-dimers concentration when studying samples with D-dimer of 500-1500 mg/L obtained with ACL TOP, with lower values obtained with VIDAS 3.</br> <br>Conclusions: Basing on our results it can be stated, that ELFA and immunoturbidymetric method are not interchangeable and should not be used in assessment of D-dimer concentration in one patient interchangeably.</br>