The letter ”P“ means ”predisposition“ in the PIRO concept for the staging of sepsis. Different methods of molecular biology enable us to determine the genetic predisposition in both monogenic and polygenic diseases. Sepsis represents an example of a polygenic disease. The determination of genetic polymorphism of inflammatory mediators, parameters of innate immunity and haemocoagulation factors represent just one approach. The DNA microarray technology holds a promise to monitor the interaction of thousands of genes simultaneously and represents the diagnostic tool of the future. It will be necessary to coordinate clinical trials in order to make good use of these diagnostic methods.

        Key words: DNA microarray – genetic polymorfism – PIRO concept – predisposition – sepsis