Journal Information
Journal ID (publisher-id): BM
Journal ID (nlm-ta): Biochem Med
Title: Biochemia Medica
Abbreviated Title: Biochem. Med.
ISSN (print): 1330-0962
ISSN (electronic): 1846-7482
Publisher: Croatian Society of Medical Biochemistry and Laboratory Medicine
Article Information
Copyright: 2015, Croatian Society of Medical Biochemistry and Laboratory Medicine
Date received: 15 December 2014
Date accepted: 30 April 2015
Publication date (electronic): 05 June 2015
Publication date (collection): June 2015
Volume: 25
Issue: 2
Pages: 203-212
Publisher ID: bm-25-203
DOI: 10.11613/BM.2015.020
Method evaluation study of a new generation of vitamin D assays
Author notes:
Corresponding author: Dietmar Enko, dietmar.enko@gespag.at
Introduction
Recently several diagnostic manufacturers have launched new 25-hydroxy-vitamin D (25[OH]D) assays, which are aligned to the National Institute of Standards and Technology (NIST) Standard Reference Materials (SRM) (NIST, Gaithersburg, Maryland). The aim of this study was to compare the performance of one liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, one enzyme linked immunosorbent assay (ELISA), and one recalibrated and previous version of a chemiluminescence immunoassay (CLIA).
Material and methods
Serum-aliquots of 198 patient samples from routine 25(OH)D analysis were measured by the ClinMass® LC-MS/MS Complete Kit (RECIPE Chemicals + Instruments GmbH, Munich, Germany), the ORGENTEC 25(OH)D3/D2 ELISA (ORGENTEC Diagnostika GmbH, Mainz, Germany), the recalibrated Immunodiagnostic Systems (IDS)-iSYS 25(OH)DS and the previous used IDS-iSYS 25(OH)D CLIA (Immunodiagnostic Systems Ltd, Boldon, United Kingdom). Bland-Altman and Deming regression analyses were calculated for methods comparison of all tested 25(OH)D assays. The LC-MS/MS method was defined as the reference method. Within-run and between-run precision measurements were performed for all methods with three different concentration levels.
Results
Compared to the LC-MS/MS method, the new IDS-iSYS 25(OH)DS and ORGENTEC 25(OH)D3/D2 assay demonstrated mean relative biases of 16.3% and 17.8%. The IDS-iSYS 25(OH)D assay showed the lowest mean bias of 1.5%. Deming regression analyses of the recalibrated IDS-iSYS 25(OH)DS and the ORGENTEC 25(OH)D3/D2 assay showed proportional differences, when compared to the reference method. All assays showed a within-run and between-run imprecision of ≤ 20% at each of the evaluated concentration levels.
Keywords: vitamin D; immunoassays; liquid chromatography-tandem mass spectrometry; reference standards; quality improvement
