procalcitonin
Pronunciation: pro-kal-sih-TOE-nin
Also written as: PCT — procalcitonin
Biomarker that rises specifically in bacterial infections, used to guide antibiotic therapy decisions.
Full Definition
Procalcitonin is a peptide precursor of calcitonin that increases significantly during bacterial infections and sepsis while remaining low in viral infections and non-infectious inflammatory conditions. Normal levels are below 0.1 ng/mL, with levels above 0.5 ng/mL suggesting bacterial infection. Procalcitonin has become increasingly important in pediatric infectious disease management for distinguishing bacterial from viral illnesses and guiding antibiotic stewardship efforts.
Usage
Usage note: Increasingly used in antibiotic stewardship; more specific for bacterial infection than CRP.
In Context
- "The elevated procalcitonin level supported initiation of empirical antibiotics." — Treatment decision rationale
- "Procalcitonin remained low despite fever, suggesting viral etiology." — Diagnostic workup interpretation