A procalcitonin assay has recently been approved for use in the United States. Unfortunately many hospitals do not run the assay in house. The principles behind procalcitonin and the current state of use are covered in a recent review in LabMedicine (reproduced in full text at Medscape).
PCT seems to be useful as an adjunct to guide antimicrobial treatment. Questions remain as to its value in diagnosing or excluding infection.