Indicator Explainer
Procalcitonin
A biomarker rising markedly in systemic bacterial infection — decision support for antibiotic pathways, not a diagnosis by itself.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Measured in emergency and intensive-care pathways for suspected sepsis, and in structured lower-respiratory-infection protocols that guide antibiotic initiation and duration.
Reading results
Surgery, trauma, shock, and some cancers raise procalcitonin without infection, while early or localised infections can leave it normal. Single values mislead; the kinetic trend across serial samples, combined with clinical assessment, is what structured protocols use. It supports — never replaces — clinical judgement about starting or stopping antibiotics.
Questions to ask a professional
- What is the trend across serial measurements, not just the single value?
- Which protocol governs antibiotic decisions in this pathway?
- What non-infectious causes of elevation apply here?