This review aims to provide physicians with an overview of the potential of
procalcitonin to guide
antibiotic therapy in
respiratory tract infections and in
sepsis. Knowledge of the strengths and weaknesses of
procalcitonin are prerequisites for a rational and safe use in clinical routine. In most
infections a true gold standard for diagnosis does not exist, therefore physicians must remain sceptical towards observational studies evaluating
procalcitonin. Interpretation of
procalcitonin levels must always include the clinical setting and knowledge of assay characteristics, particularly the setting of specific cut-off ranges and functional assay sensitivities. Highly sensitive
procalcitonin measurements, embedded in a clearly defined setting and prospectively validated with clinical algorithms were repeatedly effective in markedly reducing the (over)-utilisation of antimicrobial
therapy. Today, this concept has been proven for lower
respiratory tract infections and in pilot studies for
meningitis and
critically ill patients with
sepsis. The higher the absolute risk for adverse outcome of a patient, the more cautious physicians must remain and empirical
antibiotic therapies must be considered despite initial low
procalcitonin levels at the initial presentation. In these patients a
procalcitonin-guided shortening of
antibiotic courses seems appropriate. The prognostic utility of initial
procalcitonin measurement in
respiratory tract infections is suboptimal. Other
biomarkers including
cortisol,
human growth hormone and prohormones from
adrenomedullin and
vasopressin ("copeptin") have a superior predictive potential to estimate the risk for short and long term mortality and other adverse outcomes in different diseases. An accurate prognostic assessment has the potential to optimise the management of patients and the allocation of our limited health care resources by lowering unnecessary hospitalisations and associated cost. Future intervention studies must prove if these
biomarkers indeed improve clinical decision making and thus the overall medical management of patients.