A wide-range CRP assay based on label-free immunoassays by bio-layer interferometry
Objective This study aims to demonstrate the feasibility of using Bio-layer Interferometry(BLI)for label-free detection of peripheral blood biomarkers,using C-reactive protein(CRP)as a model molecule.Methods A total of 85 clinical remnant serum samples from routine laboratory tests were collected from Fuwai Hospital,Chinese Academy of Medical Sciences,from July 2021 to May 2022.The biotinylated anti-CRP antibody was immobilized onto streptavidin-functionalized BLI probes.The GatorPrime BLI system was used to detect series of diluted CRP standards in real-time,and to generate dynamic binding curves for establishing standard curves based on the relationship between concentration and initial binding rates.The sensitivity of the method,including the limit of blank(LoB),limit of detection(LoD),and limit of quantitation(LoQ),was evaluated according to Clinical & Laboratory Standards Institute(CLSI)guidelines.Serum samples and third-party quality control materials were used to evaluate the precision,while linearity was verified through the dilution of a high-concentration serum series.Method comparison between the label-free BLI assay and conventional clinical laboratory immunoassays was conducted using Passing-Bablok regression and Spearman correlation analysis.Results The GatorPrime BLI system demonstrated a dynamic detection range of 0.6-300 mg/L for CRP standards,and the linearity within this range was validated using serum samples.The LoB,LoD,and LoQ for this method were determined to be 0.246 mg/L,0.573 mg/L,and 2.158 mg/L,respectively.Precision analysis showed that the total laboratory imprecision of the four levels of quality control materials(21.15-57.26 mg/L)ranged from 5.8％to 9.0％,and the total imprecision of the two serum samples(2.32 mg/L and 100.06 mg/L)was 22.3％and 7.4％,respectively.Methodological comparison with two commonly used clinical laboratory immunoassays revealed a strong correlation with our method(Passing-Bablok regression:Y=-1.065+1.119X and Y=-0.452+1.034X,r=0.993 and r=0.976,P＜0.001).Conclusions The label-free BLI immunoassay method enables the detection of CRP across a broad concentration range in blood samples,with analytical performance meeting the requirements for laboratory testing.This method shows potential as a reliable and efficient alternative for CRP measurement in clinical practice.
万方数据
维普
