Procalcitonin as an acute phase marker.

Procalcitonin is a 14-kDa protein encoded by the Calc-1 gene along with calcitonin and katacalcin. The function and regulation of this protein are quite different from those of the other gene products. Blood concentrations of procalcitonin are increased in systemic inflammation, especially when this is caused by bacterial infection. Studies of its behaviour in patients with bacterial sepsis have led to the proposal that it may be a useful marker of systemic bacterial infection, with greater specificity and sensitivity than acute phase proteins such as C-reactive protein.