BACKGROUND: Vitamin D testing is becoming increasingly important with recent research demonstrating a correlation between vitamin D insufficiency and metabolic diseases, immunodeficiencies and other diseases. However, existing 25-hydroxyvitamin D (25OHD) assays lack comparability to the candidate reference method, causing difficulties in diagnosis and monitoring of vitamin D deficiency. METHODS: We looked at the accuracy of 3 automated assays (Roche Diagnostics Elecsys® Total 25OHD assay, Abbott Architect® Total vitamin D assay, Advia Centaur® vitamin D Total assay) and Diasorin® Radioimmunoassay (RIA) compared to a routine laboratory Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). RESULTS: The correlation based on Passing Bablok regression was good with the slopes between 0.95 and 1.31 and the intercepts between -3.24 and 3.68. However, a significant positive bias was observed using the Abbott Architect and the Diasorin RIA. Using published analytical goals of coefficient of variation (CV) <10% and bias <5%, most methods did not meet these criteria. Using measurement of uncertainty of 9%, most methods were able to meet criteria using quality control materials but not patient samples. CONCLUSION: Inadequacies of these assay performances are contributed by differences in method of extraction of vitamin D from vitamin D binding protein, cross-reactivities to 25OHD(2), 25OHD(3) and other vitamin D metabolites, matrix interferences and a lack of standardization.
BACKGROUND:Vitamin D testing is becoming increasingly important with recent research demonstrating a correlation between vitamin Dinsufficiency and metabolic diseases, immunodeficiencies and other diseases. However, existing 25-hydroxyvitamin D (25OHD) assays lack comparability to the candidate reference method, causing difficulties in diagnosis and monitoring of vitamin D deficiency. METHODS: We looked at the accuracy of 3 automated assays (Roche Diagnostics Elecsys® Total 25OHD assay, Abbott Architect® Total vitamin D assay, Advia Centaur® vitamin D Total assay) and Diasorin® Radioimmunoassay (RIA) compared to a routine laboratory Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). RESULTS: The correlation based on Passing Bablok regression was good with the slopes between 0.95 and 1.31 and the intercepts between -3.24 and 3.68. However, a significant positive bias was observed using the Abbott Architect and the Diasorin RIA. Using published analytical goals of coefficient of variation (CV) <10% and bias <5%, most methods did not meet these criteria. Using measurement of uncertainty of 9%, most methods were able to meet criteria using quality control materials but not patient samples. CONCLUSION: Inadequacies of these assay performances are contributed by differences in method of extraction of vitamin D from vitamin D binding protein, cross-reactivities to 25OHD(2), 25OHD(3) and other vitamin D metabolites, matrix interferences and a lack of standardization.
Authors: Karen W Phinney; Johanna E Camara; Susan S-C Tai; Lane C Sander; Stephen A Wise; Linde A C De Grande; Linda M Thienpont; Antonio M Possolo; Blaza Toman; Christopher T Sempos; Joseph M Betz; Paul M Coates Journal: J AOAC Int Date: 2017-06-16 Impact factor: 1.913
Authors: T F Cheung; K Y Cheuk; F W P Yu; V W Y Hung; C S Ho; T Y Zhu; B K W Ng; K M Lee; L Qin; S S Y Ho; G W K Wong; J C Y Cheng; T P Lam Journal: Osteoporos Int Date: 2016-03-24 Impact factor: 4.507
Authors: Mir Sadat-Ali; Abdulmohsen H Al-Elq; Iman H Al-Shaikh; Haifa A Al-Turki; Amein K Al-Ali; Abdallah A Al-Othman Journal: Saudi Med J Date: 2014-10 Impact factor: 1.484