CRP and influenza: Procalcitonin, especially when assessed in conjunction with a complete blood count and CRP, exhibits better predictive values in diagnosing bacterial infections [53], but it may also increase in cases of infections caused by mycoplasma [40], mycobacteria [64] or in certain uncomplicated viral infections like influenza [65] or Sars-CoV-2 [66]; this can be explained by inflammation caused by the activation of the immune system, leading to an inflammatory response and nonspecific elevation of inflammatory indexes.