[Infection and plasma procalcitonin]

Procalcitonin, a propeptide of calcitonin, is normally produced in the C-cells of the thyroid gland, but it's plasma level markedly increases, mostly due to extra-thyroidal production in cases of severe infections (bacterial, parasitic and fungal) with systemic manifestations, especially in the presence of septic shock. Since noninfectious inflammatory reaction, viral infection and localized bacterial infections manifest only small to modest increases of procalcitonin in plasma, procalcitonin levels may be useful in differentiating between these diseases and sepsis. In addition, it has been suggested that procalcitonin is an early and good marker of elevated cytokines in patients with sepsis, and that it's plasma level is correlated with Sepsis-related Organ Failure Assessment (SOFA) score. Since plasma procalcitonin is measured easily, quickly and accurately by immunoluminometric assay, it is useful for early diagnosis of sepsis in patients with severe systemic inflammatory response syndrome and as an indicator of severity of sepsis in such patients.