Fluorescent-Labeled Lateral Flow Test In Quantitative Detection Of C-Reaction Protein And Procalcitonin

C-Reactive Protein(CRP)and Procalcitonin(PCT)are the most representative in vitro diagnostic markers for infectious diseases.CRP level in human serum is highly correlated with bacterial or viral infection.As a specific immunological indicator of bacterial infection,PCT is also of significance for the diagnosis of sepsis.Combination of both CRP and PCT detection does not only confirm the infection but also differentiates bacterial infections from viral infections,which greatly helps determine the use of antibiotics.In this study,immunofluorescence lateral chromatographic technique was used to develop a two in one method for quantitative detection of high sensitive CRP(hsCRP)and PCT.Using this platform for screening,we selected CRP and PCT monoclonal antibodies of high-effectiveness and high specificity for pairing.The standard for CRP antibody selection is the linear reactivity range for high-concentration samples,while the standard of PCT antibody is the sensitivity for low-concentration samples.The nano-fluorescent microspheres were used as a tracer.They were covalently cross-linked with the selected antibodies using 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC)to form a highly sensitive and stable fluorescent labeled complex.This complex can be recognized and captured by the antibody coated on the nitrocellulose membrane to form a double antibody sandwich detection system.This system can be used to simultaneously detect both hsCRP and PCT in the serum samples pretreated with sample diluent.The reaction process is completed within 15 minutes,facilitating the picogram level quantitative detection of protein.To establish the traceability of hsCRP and PCT detection methods,we developed traceability maps of the two detection methods,as well as the preparation and calibration of primary and secondary calibrators.The hsCRP detection is traced to the International Federation of Clinical Chemistry(IFCC)CRM-470 reference standard;the PCT detection is traced to the inventor BRAHMS PCT LIA and Roche Elecsys BRAHMS PCT under its automation and calibration.Using the standard curve to detect clinical samples,we verified that the detection range of hsCRP was 0.1-100mg/L with sensitivity 0.5mg/L and high correlation with the reference method with R2=0.9656,and the PCT detection range was 0.1-100ng/mL with sensitivity 0.5ng/m L and R2=0.9589.Both were in accordance with the expected research target and clinical application.