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Procalcitonin (PCT)

Published: July 27, 2026Updated: August 25, 2026

Procalcitonin (PCT) is a biomarker used to diagnose bacterial infections and sepsis by measuring the level of PCT in the blood.

Quick summary

PCT levels help diagnose bacterial infections and sepsis.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
ng/mL
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Roche PCT, Brahms PCT
interpretation: {"text":"Normal range; low risk of bacterial infection.","label":"0–0.25 ng/mL"}; {"text":"Elevated levels may indicate bacterial infection or sepsis; further evaluation is recommended.","label":">0.25 ng/mL"}

Procalcitonin (PCT) is a peptide precursor of the hormone calcitonin, and its levels rise significantly in response to bacterial infections and sepsis.

Measuring PCT levels can help differentiate between bacterial and viral infections, guiding antibiotic therapy decisions.

The reference range for PCT is typically 0–0.25 ng/mL, with higher levels indicating a higher likelihood of bacterial infection or sepsis.

Frequently asked questions

What is the normal range for procalcitonin?
The normal range for procalcitonin is typically 0–0.25 ng/mL.
How is procalcitonin used in clinical practice?
Procalcitonin is used to diagnose bacterial infections and sepsis, and to guide decisions on initiating or discontinuing antibiotic therapy.
  1. 1
    Procalcitonin as a Diagnostic Marker of SepsisSource
  2. 2
    Clinical Use of Procalcitonin in Acute Infectious DiseasesSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy