A rapid and user-friendly assay to detect the Neutrophil gelatinase-associated lipocalin (NGAL) using up-converting nanoparticles

NGAL is a promising novel biomarker for acute kidney injury (AKI) and chronic kidney disease (CKD). More rapid and user-friendly methods are needed for the timely monitoring of NGAL in human urine and serum. UCP technology-based lateral flow assay (UPT-LFA) was developed for rapid, user-friendly and quantitative detection of the NGAL in human serum specimens and urine specimens. Under optimal conditions, the UPT-LFA displayed a rapid response to NGAL with a LOD of 7.68   ng/mL and detection range from 7.68 to 1000   ng/mL. The UPT-LFA method was compared with commercial immunoturbidimetry (103 urine specimens), and by ELISA (26 serum specimens), respectively. The results demonstrated that the UPT-LFA was consistent with immunoturbidimetry assay, reporting a 97.92% of positive and 92.73% of negative coincidence rates, respectively. Meanwhile, the concordance rate between UPT-LFA and ELISA, as shown by correlative regression analysis, was also high (R 2 =0.95). The whole assay can be completed within 30   min compared to 4   h consuming with ELISA. The research implies that, the UPT-LFA provides a potential to be used in point of care testing (POCT) to define early acute kidney injury with advantages of user-friendly and rapid testing, promising this new assay a bright future.