B-074 Comprehensive Performance Evaluation of a Novel CLIA for Measurement of Vitamin D Across Diverse Clinical Conditions and Status Levels

Background Vitamin D (VitD) deficiency is a global health concern requiring precise measurement for diagnosis and management. Current CLIAs, including DiaSorin, Roche, Abbott, and Beckman-Coulter, are widely used but face challenges such as standardization issues, inter-laboratory variability, and interference from metabolites and binding proteins, emphasizing the need for improved assays. Methods This study assessed the analytical performance of the Mindray CL-900i® 25-OH VitD Total assay, comparing it with DiaSorin and Roche to evaluate its suitability as an alternative for clinical VitD quantification. A total of 345 serum samples, spanning a wide range of VitD levels and diverse health conditions (pregnancy, chronic kidney disease, osteoporosis), were analyzed using DiaSorin, Roche, and Mindray. Diagnostic metrics, including sensitivity, specificity, and positive predictive value (PPV), were calculated. Bland-Altman and Spearman’s rank correlation analyses were performed. Results All assays showed strong correlations. DiaSorin-Roche achieved r=0.92, AUC=0.96. Mindray-DiaSorin and Mindray-Rochecorrelations were r=0.92 and r=0.80 with AUCs of 0.97 and 0.90, respectively. Bland-Altman analysis revealed acceptable mean biases: Roche-DiaSorin (5.72± 8.71 ng/mL), Mindray-DiaSorin (5.32±11.0 ng/mL), and Mindray-Roche (11.0±15.9 ng/mL). The best cut-off for Mindray, derived from Youden’sindex, was >32 ng/mL, while DiaSorin’s was >30 ng/mL. Mindray demonstrated high specificity (99% vs. DiaSorin; 98% vs. Roche) and PPV (98% vs. both), ensuring robust identification of VitD sufficiency and reliable deficiency diagnoses when flagged positive. Conclusion The Mindray CL-900i® assay aligns closely with reference methods, particularly DiaSorin, offering a reliable alternative for clinical VitD quantification.