Early identification of haemodynamic shock is widely acknowledged as a vital step towards improving survival. A report in the previous issue of Critical Care describes the relationship between lactate concentrations in blood samples analysed in the prehospital environment and subsequent hospital mortality. These preliminary data indicate a promising avenue of research into the treatment of haemodynamic shock. Larger observational and interventional trials are needed to confirm the clinical value of serum lactate measurement in the prehospital environment.