Procalcitonin

Summary

Procalcitonin is an endogenous 116-amino-acid peptide used clinically as a serum biomarker to diagnose bacterial infections, guide antibiotic therapy, and monitor sepsis severity. It is not administered as a drug but is measured via immunoassay. FDA-cleared PCT assays are used in ICU and emergency settings to reduce unnecessary antibiotic use and improve patient outcomes.

Mechanism of Action

Procalcitonin (PCT) is a 116-amino-acid prohormone of calcitonin produced primarily by thyroid C-cells under normal conditions, but massively upregulated by parenchymal cells throughout the body in response to bacterial infection and sepsis. It serves as a biomarker rather than a therapeutic agent; elevated serum PCT levels reflect systemic bacterial inflammation and correlate with severity of infection and sepsis. PCT-guided algorithms help clinicians decide on antibiotic initiation and discontinuation.

Routes of Administration

No administration routes recorded yet.

Goals & Uses

• Monitoring treatment response in sepsisPrognostic / MonitoringHigh
• Diagnosis of bacterial sepsisDiagnostic / BiomarkerHigh
• Risk stratification in lower respiratory tract infectionDiagnostic / BiomarkerHigh
• Prognosis in critically ill patientsPrognosticModerate
• Antibiotic stewardship guidanceTherapeutic Decision SupportHigh
• Differentiation of bacterial vs. viral infectionDiagnostic / BiomarkerHigh

Contraindications

• Sole reliance for antibiotic decisions in immunocompromised patientsClinical LimitationHigh
• Use as sole diagnostic in fungal or parasitic infectionsDiagnostic LimitationModerate

Adverse Effects

• Phlebotomy-related discomfortProceduralCommon

Drug Interactions

No drug interactions recorded yet.

Population Constraints

• Patients with medullary thyroid carcinomaDisease StateRelative
• Severe renal failure (ESRD)Organ ImpairmentRelative
• Neonates (<72 hours of life)AgeRelative
• Post-major surgery or trauma patientsClinical ConditionRelative

Regulatory Status

• European UnionApprovedApproved: Diagnosis and monitoring of sepsis, Antibiotic stewardship in bacterial infectionsCE-marked in vitro diagnostic; widely used across EU member states per BRAHMS (Thermo Fisher Scientific) regulatory submissions.
• United StatesApprovedApproved: Risk stratification of patients with sepsis, Guidance of antibiotic therapy initiation and discontinuation in lower respiratory tract infections and sepsisFDA-cleared as an in vitro diagnostic device (510(k)); BRAHMS PCT sensitive KRYPTOR and Elecsys BRAHMS PCT assays cleared. Not approved as a therapeutic drug.
• United KingdomApprovedApproved: Sepsis risk stratification, Antibiotic decision support in respiratory tract infectionsNICE recommends PCT testing in certain sepsis and antibiotic stewardship contexts; UKCA/CE-marked diagnostic assays available.

FDA cleared multiple PCT immunoassay tests (e.g., BRAHMS PCT assay by Thermo Fisher) for use in risk stratification of patients with sepsis and lower respiratory tract infections. CE-marked in the EU. Not a therapeutic drug; regulatory clearance applies to in vitro diagnostic devices.

Evidence & Sources

No sources recorded yet.