[Procalcitonin - importance for the diagnosis of bacterial infections]

In contrast to Calcitonin that is primarily synthesized in the thyroid, Procalcitonin is the prohormon that is synthesized in many different tissues of infected organs. In order to be useful for the diagnosis of mild, localized or early infections the assay needs to have a sensitivity that can measure within normal limits (0.02 microg/L). We were able to show that a Procalcitonin algorithm influences the outcome of respiratory infections in terms of minimizing use of antibiotics and duration of antibiotic treatment. High concentrations, especially when seen over time, indicate a high risk of a severe outcome. In this respect, Procalcitonin is superior to other infection markers such as C-reactive Protein (CRP). High Procalcitonin levels can also be seen in non bacterial diseases such as malaria, severe trauma, burns and medullar carcinoma of the thyroid. Together, Procalcitonin has improved the diagnosis of bacterial infections, however should always be used in context with other laboratory markers, clinical exam and medical history.