CRP and viral infectious disease: In this study, focusing on two prevalent clinical syndromes that are difficult to diagnose as bacterial or viral, we compared the diagnostic performance of the host-protein signature not only to commonly applied CRP and PCT, as documented previously [25, 27, 28, 30], but also in a head-to-head manner to multiple cutoffs of IL-6, HNL, and several prediction rules that have been reported as candidate tools for aiding the clinician in discriminating between bacterial and viral infection.