Normal Reference Range for Procalcitonin
May 28, 2022
Source: Cainiu Health
Dr. Jiang Weimin
Introduction
Procalcitonin (PCT) is measured in venous blood, with normal reference ranges of 0.15 ng/mL for adults and 2 ng/mL for newborns within 72 hours of birth. Under normal conditions, PCT is primarily secreted by thyroid C cells, and circulating PCT levels are very low in healthy individuals. PCT is an inflammatory biomarker that reflects systemic bacterial infection.
Procalcitonin (PCT) is a protein with excellent stability both in vivo and in vitro. Elevated serum PCT levels are closely associated with bacterial infection. What, then, is the normal reference range for procalcitonin?
Normal Reference Range for Procalcitonin
When measured in venous blood, the normal PCT level in adults is ≤0.15 ng/mL; in neonates within 72 hours of birth, it is ≤2.0 ng/mL. Under physiological conditions, procalcitonin is predominantly secreted by thyroid C-cells, and its concentration in circulating blood remains very low. During systemic bacterial infection, however, PCT is synthesized ectopically in multiple extrathyroidal tissues and subsequently released into the bloodstream, resulting in a marked increase in circulating PCT levels. Thus, PCT serves as a specific inflammatory biomarker reflecting systemic bacterial infection. In severe systemic bacterial infections, PCT levels rise significantly—generally correlating with infection severity: the more severe the infection, the higher the serum PCT concentration.
Procalcitonin circulates in the blood as an inactive precursor peptide without hormonal activity but possessing anti-inflammatory properties. Its plasma concentration increases markedly during severe infection. In healthy individuals, PCT levels remain within the normal reference range. However, when the body suffers severe infection or assault by various pathogenic microorganisms, PCT levels rise substantially. Therefore, clinicians routinely use PCT measurement to aid in diagnosing infection.
Higher PCT values generally indicate more severe infection. Any elevation detected in routine clinical practice warrants prompt evaluation and intervention. We hope this explanation has been helpful!
