title: Distinction between bacterial and viral infections.
abstract: OBJECTIVE
  To commence proper treatment as rapidly as possible and to reduce unnecessary antibiotic treatments, timely knowledge of whether the infection is bacterial or viral in origin would be beneficial for the clinician. As a reliable prediction of the causative agent of bacterial infection is not possible based on clinical features, there is an ongoing need for sensitive and specific markers of bacterial infection.
  
  
  RESULTS
  The most common differential diagnosis methods are reviewed here. It is also demonstrated that the measurement of the expression of complement receptors, particularly CR1 (CD35), on neutrophils can be a useful preliminary test to differentiate between bacterial and viral infections. In addition, a novel marker of local and systemic bacterial infections designated 'clinical infection score (CIS) point', which incorporates quantitative analysis of complement receptors on neutrophils and standard clinical laboratory data and displays 98% sensitivity and 97% specificity in distinguishing between bacterial and viral infections, is presented.
  
  
  CONCLUSIONS
  We conclude that the diagnostic yield of measured individual variables in distinguishing between bacterial and viral infections increases upon combination.
authors.affiliation: Department of Biochemistry, University of Turku, Turku, Finland. jarnuu@utu.fi
authors.forename: Jari
authors.initials: J
authors.lastname: Nuutila
authors.forename: Esa-Matti
authors.initials: EM
authors.lastname: Lilius
mesh_terms: D001424:Bacterial Infections / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D015415:Biomarkers; D017714:Community-Acquired Infections / Q000175:diagnosis; D003937:Diagnosis, Differential; D006801:Humans; D009504:Neutrophils / Q000276:immunology; D017463:Receptors, Complement 3b / Q000097:blood / Q000276:immunology; D012680:Sensitivity and Specificity; D014777:Virus Diseases / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology
chemical_list: D015415:Biomarkers; C509991:CR1 protein, human; D017463:Receptors, Complement 3b