Procalcitonin (PCT) assay kit (quantum dot immunoassay)Clinical diagnostic significance of PCTInflammatory biomarker PCTProcalcitonin (PCT) is a precursor peptide of the hormone calcitonin (CT). After CT mRNA translation, PCT is enzymatically hydrolyzed into a mature CT with a final product of 32 amino acids. The PCT content in normal human serum is extremely low. After being infected by microorganisms, the CALC-I gene is induced to express and promote PCT secretion, reaching its peak after 8 hours. Currently, PCT is considered a biomarker for systemic inflammatory response syndrome, which can guide treatment, reduce antibiotic use, diagnose sepsis, and improve long-term outcomes.Guide the use of antibioticsAccording to research by the World Health Organization, only 20 out of every 100 respiratory infections require antibiotic treatment. However, using traditional diagnostic bacterial infection cultivation methods often results in delays. Therefore, a biomarker specifically targeting bacterial infections is the most helpful. Research has found that PCT can serve as an important indicator to distinguish between bacterial and non infectious inflammatory causes, as well as to differentiate between bacterial and viral infections. Moreover, the dynamics of PCT levels have significant prognostic implications.Diagnosis of sepsisCritical patients often exhibit systemic inflammatory response syndrome (SIRS). When SIRS is present and infection is confirmed or suspected, the term sepsis is used. In severe infections, most pro-inflammatory cytokines (such as TNF-a, ex-1b, or ex-6) only increase briefly or intermittently. In sepsis, PCT levels increase several to several times, and this increase upon admission is typically associated with the severity of the condition and subsequent mortality. Various studies and reviews have shown that PCT has higher diagnostic accuracy compared to other parameters for diagnosing sepsis.  references[1] Becker K L, Nylé n E S, White J C, et al. Clinical review 167: Procalcitonin and the calcitonin gene family of peptides in inflammation, infection, and sepsis: a journey from calcitonin back to its precursors.[J]. Journal of Clinical Endocrinology & Metabolism, 2004, 89(4): 1512.[2] Weglohner W R D, Struck J S C, Morgenthaler N, et al. Isolation and characterization of serum procalcitonin from patients with sepsis.[J]. Peptides, 2001, 22(12): 2099-103.[3] Mü ller B, White J C, Nylé n E S, et al. Ubiquitous expression of the calcitonin-i gene in multiple tissues in response to sepsis[J]. Journal of Clinical Endocrinology & Metabolism, 2001, 86(1): 396.[4] Levin A S. Overcoming Antimicrobial Resistance[J]. Brazilian Journal of Infectious Diseases, 2008, 12: 10-21.