Studies show that procalcitonin (PCT) may be a useful tool in aiding the diagnosis of pneumonia in a newborn intensive care unit (NICU) as well since it elevates quickly compared to WBC and C-reactive protein (CRP), is elevated in bacterial (but generally not viral or fungal) infections, and downtrends rapidly after treatment in patients with normal renal function. However, it is still controversial if PCT can be applied as a diagnostic measure, and not merely as a tool for de-escalation of antibiotics [53]. This evidence concerns the gene CRP and susceptibility to pneumonia measurement.