Procalcitonin LiquiColor^® Assay

Sepsis is a term given to an inflammatory response to infection. This infection is usually bacterial in origin but sepsis can also be the result of fungal, parasitic and viral infections, although to a much smaller degree. Upon bacterial infection, an innate immune response is initiated involving numerous mechanisms that attempt to contain the infection.

PCT is currently utilised as a marker in the diagnosis of sepsis. It is a precursor peptide of calcitonin; a hormone involved in calcium homeostasis. Under normal circumstances, PCT is cleaved enzymatically into smaller peptides to yield mature calcitonin, meaning that low levels of PCT are present in serum. During a microbial infection, circulating levels of calcitonin precursors, including PCT, increase up to several thousand-fold.

Sepsis can quickly develop into severe sepsis and septic shock, conditions associated with signs of end organ damage and hypotension. At this stage, the risk of death is high and increases drastically the longer the initiation of treatment is delayed for. However, if a patient receives antimicrobial therapy within the first hour of diagnosis, their chances of survival are close to 80%. This short window is therefore often coined “the golden hour”.

Determining the amount of circulating PCT is an important step in the diagnosis of sepsis. When the use of PCT and other sepsis markers, Interleukin-6 and Interleukin-8, are compared for patients who were admitted to hospital with SIRS criteria and/or a suspected infection, PCT was found to improve the predictive value of detecting sepsis from 77% to 94% .