Due to the increasing number of Russian citizen’s visits to the countries of the tropical countries, the number of cases of imported endemic infectious diseases, mostly dengue fever (DF), also had increased. Dengue fever is an acute viral vector-borne disease, accompanied by fever and intoxication, with the possible development of hemorrhagic syndrome and shock, in which survival depends from the time of initiation of intensive therapy. The greatest incidence of DF in Moscow is associated with travelling to tropical countries during the Christmas holidays, which coincides with the seasonal rise in the incidence of influenza and other ARTI’s. However, ambulance medical workers in most cases (except for the cases of calling the ambulance team to the medical organization during the working hours of the laboratory) are not able to carry out and assess even the minimum of hematological parameters. Therefore, when diagnosing and determining the phase of the disease and its severity, the ambulance medical worker can rely only on epidemiological and clinical data. In this regard, a group of authors proposed an algorithm for early diagnosis and treatment of patients with suspected dengue fever at the prehospital stage, taking into account clinical symptoms and standardized tourniquet test.