[Procalcitonin, a new marker for bacterial infections]

Procalcitonin (PCT), the precursor protein of the hormone calcitonin, appears to be an early marker of the presence of severe systemic infection. High serum concentrations are associated with severe systemic bacterial, parasitic or fungal infections. In contrast, PCT is generally not induced by severe viral infections or inflammatory reactions of non-infectious origin. Hence, PCT can be used for differential diagnosis of bacterial and viral meningitis. PCT may be helpful in the differentiation between infectious and non-infectious origin of systemic inflammatory response syndrome (SIRS) and acute respiratory distress syndrome (ARDS), pancreatitis, cardiogenic shock and acute rejection of organ transplants. PCT monitoring may be useful in patients with high risk of bacterial infection (major surgery, trauma, immunocompromised patients). PCT is a very stable molecule in vitro, and its measurement requires only 20 ml of plasma or serum and can be done within 2 hours.