What is the significance of a procalcitonin (PCT) level in the face of questionable pneumonia? How reliable is a PCT determination in the decision to treat or not to treat with an antibiotic?
—Smriti Goyal, MD, Atlanta

PCT levels are elevated in sepsis and have shown utility as prognostic markers for disease severity among inpatients with pneumonia. There is additional interest in its use for guiding antibiotic choices in patients who present with lower respiratory tract infection that may not be bacterial in origin. Such studies are hampered by the obvious fact that community-acquired pneumonia is a clinical diagnosis. The key point is that the PCT test must be ultrasensitive with a rapid turnaround, and most community laboratories are presently not able to provide these diagnostics.
—Cedric W. Spak, MD, MPH (118-9)