Can we tell infection from tissue damage as a cause of inflammation? A strategy using clinical chemistry and patten recognition methods
1Institute of Biomedicine, University of Gothenburg, Göteborg, Sweden
Both invasive infection and sterile tissue damage trigger systemic inflammation with fever and production of acute phase proteins. This poses a problem in diagnosing infection in patients who are already in an inflamed state due, e.g., to cancer, autoimmunity or massive trauma and there is currently no biomarker that can solve this problem. We postulated that by measuring a wide range of biochemiacal variables, different patterns could be revealed, representing microbe-driven and damage-driven inflammation. In all, 113 clinical chemical variables were mearsured in 42 febrile neutropenic patients with hematological malignancies. Infection was diagnosed by extensive microbiological work-up and the diagnosis was made by an independent observer. Using O-PLS (orhtogonal projection onto latent structures), a model that could segregate infected from non-infected patients was achieved based on 40 of these variables; the model correctly identified the infectious status of nine out of ten subsequently recruited febrile neutropenic hematology patients. Variables of importance for predicting infection included certain acute phase proteins, cytokines, measures of coagulation, iron-turnover, metabolism and organ stress. Our findings suggest that clinical decision-making can be supported by multivariate analysis of chemical variables distinguishing "patterns" that characterize different disease states.