Evaluation of blood lactate level and its trend are important morbidity and mortality predictive factors. In prehospital care, lactate level is more sensitive marker and have better prognostic value in severe trauma than basic vital signs. Worse outcome is associated with levels between 2 - 4 mmol/l. Measurement of lactate level in venous or capillary blood is quick and simple method with minimal risks and with no special needs for medical staff training. In spite of good availability of this method in the Czech Republic the method feasibility has never been analysed in patients with severe trauma.