Procalcitonin (PCT): blood test, levels and interpretation of results

🏾 Contents:

🏾 Procalcitonin test

In general, there are no special preparations to make before testing, it is a blood test that can be done at any time and does not require fasting, except whether your blood sample will be used for further testing.

🏾 What is the normal value of procalcitonin ?

In healthy individuals, procalcitonin is rapidly transformed into calcitonin. Therefore, PCT values in uninfected individuals are very low < 0.1 µg/L. Levels greater than 0.25 ng/mL may indicate the presence of an infection.

Note: Values should be interpreted based on the clinical context.

🏾 Interest in testing procalcitonin

Le médecin peut demander un test de procalcitonine pour :

The doctor may order a procalcitonin test to

🏾 Procalcitonin versus CRP

The PCT rises very early after the start of the infection (3 hours), its half-life is quite short (about 24 hours) and the rate decreases rapidly in the event of improvement, making it possible to shorten duration of antibiotic treatment

CRP is a good marker of the acute phase of inflammation, its use to distinguish infection bacterial from a viral infection is less obvious.

🏾 Is procalcitonin elevated in viral infections?

The concentration of procalcitonin increases in bacterial infections but remains low in viral infections and inflammatory diseases. The change is rapid and the molecule is stable, making it a potentially useful marker for distinguish between bacterial and viral infections.

🏾What are the advantages of PCT over other biomarkers?

The advantages of PCT over older markers include:

🏾How to reduce procalcitonin?

Serum procalcitonin levels decline rapidly with appropriate antibiotic treatment (48-72 hours after admission).


  1. J.O. Robinson - Utilité de la procalcitonine dans le diagnostic et le suivi des infections chez les patients neutropéniques fébriles
  2. La CRP ou la PCT: Quel est le meilleur marqueur d'infection bactérienne?
  3. University of Nebraska Medical Center - Procalcitonin (PCT) Guidance
  4. thermofisher - Understanding Procalcitonin
  5. Derrick A - Procalcitonine
  6. NIH - Procalcitonine TEST
  7. A. toitot - Les marqueurs du sepsis une femme enceinte porteuse d’une coronaropathie ?