The introduction of a new device into a laboratory requires verification of the existing analytical features and reference intervals established by the manufacturer. The reference intervals are established on a large number of healthy population of Central Europe, where we belong. For verification, it is necessary for at least 20 healthy respondents to check these reference intervals. They will be accepted if 10% or less of the respondents are out of interval, or they will not be accepted if more than 10% of the respondents are out of it. Hemostasis as a term means stopping bleeding, and the hemostasis system in the human body has the role of keeping blood in the fluid state under physiological conditions and when the injury occurs to stop the bleeding. Such a system consists of blood vessels, platelets, coagulation factors, coagulation inhibitors and fibrinolytic system. Ali of these hemostasis factors are tested by laboratory tests and thus reveal which pari of the system is a problem. The basic coagulation tests used to detect blood clotting disorders are: prothrombin time (PV), activated partial thromboplastin time (APTV), thrombin time (TV), fibrinogen concentration, platelet aggregation, and platelet aggregation assay. These are irreplaceable routine tests, but when it comes to bleeding, where they need to intervene urgently, they are not useful. Their disandvantage is long duration of analysis (about 40 minutes) .Therefore, in these cases, ROTEM has 4 channels and within 20 min results of the analysis that indicate the cause of bleeding, depending on the choice of tests. 2 situations associated with high risk of bleeding are the operation and trauma by itself, or because of the problem of blood clotting. Among the surgeries, high risk of bleeding is in cardiac, vascular, liver transplants, hip replacement and obstetric intervention. Patients due to bleeding have to undergo blood transfusion and / or re-operation, so it is important to know the cause of bleeding and treat it appropriately to avoid unnecessary transfusions. The importance of ROTEM is just to distinguish surgical bleeding from clotting disorders. From the curve called temogram except coagulation, fibrinolysis is also apparent, so-called viscoelastic methods. Sonclot and TEG are the predecessors of ROTEM, but due to their performance failures they did not last long. The benefits of ROTEM are simple execution with on-screen instructions and electronic pipette, speed of performance, additional informations which provide and shorten the patient's stay at the hospital, and thus reduces costs. Tests that are offered include EXTEM (extemal clotting pathway), INTEM (internal clotting pathway), FIBTEM (fibrinogen function inhibiting platelet function), HEPTEM (heparinase) and APTEM (aprotinin fibrinolysis inhibitor). Based on 22 respondents, reference intervals for the diagnostically significant parameters of FIBTEM, lNTEM and EXTEM tests are confirmed, HEPTEM is interpreted in relation to INTEM and APTEM compared to EXTEM.