It is quite clear that clinicians need reliable marker for bacterial infections that would allow an early diagnosis, inform about the course and prognosis of the disease and facilitate therapeutic decisions.9 Procalcitonin covers these features better as compared to other, more commonly used biomarkers (such as CRP).10 It has been shown recently that procalcitonin guidance substantially reduces antibiotic use in community-acquired pneumonia without compromising patients' safety. 11, 12 However, the efficacy and safety of PGAD in hospitalized patients with undefined fever has not been previously investigated.