Procalcitonin (PCT) is the main marker of disorders that are accompanied by sepsis. The PCT levels in blood are elevated during the systemic inflammation. In addition, the concentration of PCT closely correlates with the severity of inflammation, which further supports the diagnostic value of the marker. While in normal conditions the amount of non-cleaved PCT in blood is low, it increases during systemic inflammation and sepsis.
PCT is a prohormone consisting of 116 amino acids and can be processed into three fragments: N-terminal PCT, calcitonin and katacalcin (Figure 1). HyTest is now launching new mAbs P123, P124, and P135 targeted to N-terminal PCT (Cat.# 4PC47), mAbs P138, P139, and P141 targeted to calcitonin (Cat.# 4C10cc), and mAb P160 targeted to katacalcin (Cat.# 4PC47).
Figure 1. Processing of PCT. PCT is a small prohormone (~13 kDa) consisting of three parts: N-terminal PCT, calcitonin and katacalcin. In normal conditions, the hormonally active calcitonin can be found in blood whereas the basal level of PCT is very low. The “inflammatory” PCT detected in blood during systemic inflammation is not produced in C-cells but is instead produced in other tissue types.
For the pairs with the new clones, we have able to achieve a sensitivity up to 1.5 pg/mL and linearity up to 800 pg/mL showing good correlation in our in-house chemiluminescence (CLIA) assay and commercially available PCT assay with correlation (R2) more than 0.98 (Figure 2). In Lateral flow platform the sensitivity is also around 0.01 ng/mL showing good correlation in our in-house assay and commercially available assay with correlation (R2) more than 0.94.
Figure 2. Correlation of new HyTest PCT in-house assay P139-P135 with commercially available PCT assay. Clinical sample amount n = 103.
The assay new pairs have no or very low cross-reactivity to calcitonin, katacalcin, CGRP1, and CGRP2. Pair recommendations for the new clones in CLIA and LF platforms are shown in table 1.
Table 1. Capture-detection pair recommendations for new PCT clones in CLIA and LF platform. Best pairs are shown in bold.
Cat# 4C10 / 4C10cc: Calcitonin, human, antibody
Cat# 4PC47: Procalcitonin, human, antibody
Cat# PPC3: Polyclonal anti-procalcitonin (PCT)
Cat# 8PC5: Recombinant human procalcitonin