C-Reactive Protein or Procalcitonin Combined with Rhinorrhea for Discrimination of Viral from Bacterial Infection in Hospitalized Adults of Non-Intensive Care Medical with Lower Respiratory Tract Infection

Background: Whether procalcitonin (PCT) or C-reactive protein (CRP) combined with some clinical characteristics can better distinguish viral from bacterial infection is not clear. The aim was to assess the ability of PCT or CRP combined with clinical characteristics to distinguish between viral and bacterial infections in hospitalized non-intensive care unit (ICU) adults with lower respiratory tract infection (LRTI).Methods: This was a post-hoc analysis of a randomized clinical trial previously conducted among LRTI patients. The ability of PCT, CRP, and PCT or CRP combined with clinical characteristics to discriminate between viral and bacterial infection were estimated by portraying receiver operating characteristic (ROC) curves among patients with only vial or typical bacterial infection .Results: In total, 209 patients (virus 69%, bacteria 31%) were included in this study. When using CRP or PCT to discriminate between viral and bacterial LRTI, the optimal cut-off point were 22mg/L and 0.18ng/ml, respectively. When the optimal cut-off for CRP (≤22ml/L) or PCT (≤0.18ng/ml) combined with rhinorrhea was used to discriminate viral from bacterial LRTI, the AUCs were 0.81 (95% CI, 0.75–0.87) and 0.80 (95% CI, 0.74–0.86), respectively. When CRP≤22ml/L, PCT≤0.18ng/ml and rhinorrhea were combined, the AUC was 0.86 (95% CI, 0.80–0.91), which was statistically significant higher than that when CRP(≤22mg/L) or PCT (≤0.18ng/mL) was combined with rhinorrhea (p=0.0107 and p=0.0205).Conclusions: Either CRP≤22mg/L or PCT≤0.18ng/mL combined with rhinorrhea could help distinguish viral from bacterial infection in hospitalized non-ICU adults with LRTI. When rhinorrhea was combined together, discrimination ability can be further improved.