Procalcitonin (PCT) is a peptide precursor of the hormone calcitonin, and it plays a significant role as a biomarker for bacterial infections, especially sepsis.

• Normally produced in small amounts by the thyroid gland.
• During systemic bacterial infections, many tissues in the body begin producing PCT in large quantities.
• Its levels rise rapidly (within 2–6 hours) in response to bacterial toxins and systemic inflammation

• Helps distinguish bacterial infections from viral or non-infectious causes of inflammation.
• Higher levels of PCT are strongly associated with severe bacterial infections and sepsis.
• It is used to:
  Support early diagnose of sepsis
  Monitor progression or resolution of infection

• <0.5 ng/mL: Low risk of severe sepsis and/or septic shock
• >2 ng/mL: High risk of severe sepsis and/or septic shock