Evaluation of a multiplexed assay for six urinary proteins based on liquid microarray analysis technology

Proteinuria serves as a critical indicator in the progression of chronic kidney disease. The quantification of urinary protein is instrumental in diagnosing kidney disease and monitoring therapeutic efficacy. Nephelometry and turbidimetric immunoassay are predominantly employed for the quantitative detection of various urinary proteins. We developed a quantitative detection method for six proteins in urine utilizing the flow fluorescence luminescence method on the Luminex®200™ detection platform. This study aims to evaluate the clinical performance and accuracy of the method. The sensitivity, precision, recovery, linearity, and interference metrics for the method meet the needs of clinical applications. The correlation coefficient (r) between the results of the method and nephelometry immunoassay on SIEMENS BNII platform ranged from 0.9375 to 0.9847, indicating a strong linear relationship. The results of the Bland-Altman analysis indicated that the systematic bias between the two methods was minimal. Additionally, Passing-Bablok regression analysis, both including and excluding outliers, was conducted on the clinical trial data. The findings demonstrated consistency between the two methods, with the expected confidence interval of bias remaining within the allowable error limits, indicating no significant discrepancy. This urine six protein quantification method demonstrates satisfactory performance, meeting the standards necessary for medical diagnosis and clinical application.