[Infectious diseases: current diagnostic methods].

A microbiological diagnosis is either based on the direct detection of the pathogen or on the reaction of the host (indirect method). Many pathogens, in particular small bacteria and viruses, are undetectable by culture or difficult to cultivate. Molecular methods for the direct detection of such pathogens have been widely introduced in many microbiological laboratories within the past few years. The characteristics of these methods as well as new culture methods and new serological tests are discussed.