Procalcitonin measures how likely a bacterial infection is, especially when doctors are concerned about sepsis or a serious systemic infection.

Quick scoop

  • Low procalcitonin usually suggests a bacterial infection is less likely.
  • Higher procalcitonin can point toward a more significant bacterial infection, including sepsis.
  • It is often used to help decide whether antibiotics are needed or whether they can be stopped sooner.

What it does not do

  • It is not a standalone diagnosis.
  • It does not perfectly distinguish every bacterial infection from every viral or noninfectious condition.
  • Doctors interpret it together with symptoms, exam findings, and other tests.

Simple way to think about it

If CRP is a general “inflammation” signal, procalcitonin is more of a bacterial infection signal. In practice, it helps clinicians judge whether an infection is likely bacterial and how severe it may be.

If you want, I can also explain normal ranges and what different procalcitonin levels usually mean.