A rapid point-of-care assay accurately measures vitamin D

• Published in: Journal of endocrinological investigation Vol. 44; no. 11; pp. 2485 - 2492
• Main Authors: Albrecht, K., Lotz, J., Frommer, L., Lackner, K. J., Kahaly, G. J.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.11.2021; Springer Nature B.V
• Subjects: Cholecalciferol - analysis; Cholecalciferol - blood; Dimensional Measurement Accuracy; Endocrinology; Fluorescent Antibody Technique - methods; Humans; Immunofluorescence; Internal Medicine; Luminescent Measurements - methods; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolic pathways; Original; Original Article; Point-of-Care Systems; Rapid On-site Evaluation; Reproducibility of Results; Vitamin D; Vitamin D Deficiency - blood; Vitamin D Deficiency - diagnosis; Vitamin D serum levels; Point-of-care; Immunofluorescence assay; Chemiluminescence assay; Rapid assay
• ISSN: 1720-8386; 0391-4097; 1720-8386
• DOI: 10.1007/s40618-021-01575-8

Purpose Vitamin D (VitD) is a pleiotropic hormone with effects on a multitude of systems and metabolic pathways. Consequently, the relevance of a sufficiently high VitD serum level becomes self-evident. Methods A rapid immunofluorescence assay designed for the point-of-care measurement of serum VitD 3 solely was tested. Inter- and intra-assay validation, double testing and result comparison with a standardized laboratory method were performed. Results An overall linear correlation of r  = 0.89 (Pearson, 95% CI 0.88–0.92, p  < 0.01) between the point of care and the conventional reference assay was registered. Accuracy and precision were of special interest at cut-points (10 ng/ml [mean deviation 1.7 ng/ml, SD 1.98 ng/ml, SE 0.16 ng/ml], 12 ng/ml [MD 0.41, SD 1.89, SE 0.19] and 30 ng/ml [MD − 1.11, SD 3.89, SE 0.35]). Only a slight deviation was detected between the two assays when using fresh ( r  = 0.91, 95% CI 0.86–0.94, p  < 0.01) and frozen serum samples ( r  = 0.86, 0.82–0.89, p  < 0.01). Results remained steady when samples were frozen several times. Inter- and intra-assay validation according to the CLSI protocol as well as multiuser testing showed stable results. Conclusion This novel, innovative, and controlled study indicates that the evaluated rapid point of care VitD assay is reliable, accurate, and suited for clinical practice.