[Critical analysis of different methods used for toxicology screening in emergency laboratory]. / Analyse critique des différentes méthodes utilisées pour le dépistage toxicologique dans un laboratoire d'urgence.

Emergency analysis in toxicology is a difficult exercise. It involves in diagnosis, prognosis and the treatment of intoxication. Several methods exist in emergency screening. We have distinguished three large groups. Based on specificity: screening methods of medicament family (chemical methods and immunoassays) with benzodiazepines, tricyclic antidepressants, barbiturates and phenothiazines; complementary screening methods (thin layer chromatography and high pressure liquid chromatography) for a wider screening and finally quantitative methods (enzymatic, immunoassay, spectrometry and chromatography) specific to a molecule. The first group allows a rapid qualitative research according to medicament class but lacks specificity. The second group represented by the Remedi system, offers a larger screening of molecules but is more expensive and cannot detect classic molecules. The third group allows a precise dosage but is restricted to one molecule. We need one or the other of methods following clinical context and the type of molecule. In our laboratory, we have eliminated barbiturates and benzodiazepines research. We search only tricyclic antidepressants, salicylates and paracetamol. The Remedi system acts as a complement. It is essential to have a good knowledge of the limits and specificity of each method in order to allow the clinician to see the interpretation of the given result. The execution period and the quality of analytical result depend on dialogue between analyst and clinician before and after analysis.