procalcitonin
Pronunciation: pro-kal-si-TOH-nin
Biomarker used to distinguish bacterial from viral infections and guide antibiotic therapy duration in critically ill patients.
Full Definition
Procalcitonin is a peptide precursor of calcitonin that becomes elevated in bacterial infections and sepsis, but typically remains low in viral infections and non-infectious inflammatory conditions. It serves as a valuable biomarker for diagnosis of bacterial infections, assessment of sepsis severity, and guidance of antibiotic therapy duration. Levels above 0.5 ng/mL suggest bacterial infection, while levels above 2.0 ng/mL indicate severe bacterial infection or sepsis. Serial measurements can help monitor treatment response and guide antibiotic de-escalation or discontinuation.
Usage
Usage note: Often abbreviated as PCT in laboratory reports and clinical notes.
In Context
- "Procalcitonin levels remained elevated despite 48 hours of appropriate antibiotic therapy." — ICU progress note
- "The low procalcitonin supported discontinuation of empiric antibiotics." — Infectious disease consultation