Procalcitonin as a replacement of C-reactive protein in diagnostics of CAP

Do you think procalcitonin has a potential to replace C-reactive protein as the first-line diagnostic study in patients with suspected community-acquired pneumonia?

Mark Woodhead: There are theoretical reasons why procalcitonin might be a better marker of bacterial infection and therefore might be better than C-reactive protein at excluding a bacterial infection or in patients where you might need to give antibiotics. There are a lot of studies now that have looked at procalcitonin. What we lack are studies that directly compare procalcitonin with C-reactive protein. There are studies of C-reactive protein alone, there are studies of procalcitonin alone; both looked to be useful molecules.

C-reactive protein is cheap, procalcitonin is more expensive, so at the moment there is a theoretical benefit, but we do not know in practice whether that is the case, because the direct head-to-head studies have not been done.