The current international consensus guidelines for the management of sepsis and septic shock emphasize the need to establish a rapid method to diagnose sepsis (1). Currently, procalcitonin (PCT) is used as a marker to diagnose sepsis or severe sepsis (2). However, a meta-analysis of PCT showed that this marker has poor diagnostic utility for differentiating sepsis from other non-infectious causes. Thus, better biomarkers of sepsis are needed (3). As a result, it is still a challenge to rapidly

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... nd accurately diagnose sepsis and severe sepsis. We previously identified a sepsis-specific novel form of CD14, the soluble CD14 subtype (sCD14-ST: renamed presepsin). To measure presepsin specifically, we developed a two-step sandwich enzyme-linked immunosorbent assay (ELISA), and demonstrated that presepsin was elevated specifically in septic patients (4). Receiver operating characteristic (ROC) curve analysis of presepsin revealed that presepsin is a more specific and sensitive marker for sepsis compared with conventional markers of sepsis, including interleukin-6 (IL-6) and PCT (5). Although the first generation two-step ELISA was sufficient to evaluate presepsin as a diagnostic marker for sepsis, this assay was not convenient and lacked the rapidity and precision that is required for routine presepsin tests in intensive care units. In this letter, we describe the development and evaluation of a one-step ELISA that uses recombinant presepsin as a new standard. The two-step ELISA measured plasma presepsin levels within 4 h, and concentrations were extrapolated based on recombinant CD14 (S286C) antigen (approx. 40 kDa) as the standard. However, an analysis of native presepsin in septic patients revealed that this protein consists of the N-terminal 13 kDa fragment of the CD14 protein wwhen examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under non-reducing conditionsx (6).