Abstract: A method is provided for determining the type of an infectious pathogen in a patient who is suspected to be suffering from an infectious pathogen. The method involves first measuring the amounts of a plurality of markers in a body fluid sample of the patient. The markers of interest are produced by the patient as part of that patient's innate immune response to the presence of the infectious pathogen and are indicative of the type of the infectious pathogen in the patient. Next, a marker profile is identified based on the measured amounts of the plurality of markers. Finally, if the marker profile is indicative of an infection, then the type of infectious pathogen within the patient is determined from the marker profile. In preferred embodiments, any individual marker is either an mRNA or a protein. Methods for identifying suitable markers and kits are provided as well.