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Evaluation of two fully automated immunoassay based tests for the measurement of 1α,25-dihydroxyvitamin D in human serum and comparison with LC-MS/MS

Spanaus, Katharina ; von Eckardstein, Arnold

In: Clinical Chemistry and Laboratory Medicine (CCLM), 2017, vol. 55, no. 9, p. 1305-1314

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    Titre
    • Evaluation of two fully automated immunoassay based tests for the measurement of 1α,25-dihydroxyvitamin D in human serum and comparison with LC-MS/MS
    Auteur
    • Spanaus, Katharina. Institute of Clinical Chemistry, University Hospital of Zurich, Zurich, Switzerland
    • von Eckardstein, Arnold. Institute of Clinical Chemistry, University Hospital of Zurich, Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Clinical Chemistry and Laboratory Medicine (CCLM), 2017, vol. 55, no. 9, p. 1305-1314. De Gruyter
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:332335
    Summary
    AbstractBackground: 1α,25-Dihydroxyvitamin D [1,25(OH)2 vitD] is the bioactive form of vitamin D. Due to the very low concentrations of 1,25(OH)2 vitD in the blood and its lipophilic character, measurement of this parameter is analytically challenging. Requiring preceding manual extraction steps before analysis, previous assays have been laborious. Methods: In the presented study, we evaluated the performance of two immunoassays from DiaSorin and from Immunodiagnostic Systems (IDS) which combine fully automated extraction and measurement of 1,25(OH)2 vitD. Imprecision and linearity were verified according to Clinical and Laboratory Standards Institute EP15-A3 and EP6-A guidelines, respectively. Ninety-three patient serum samples sent to our institute for determination of 1,25(OH)2 vitD, as well as 20 Vitamin D External Quality Assessment Scheme (DEQAS) samples, were used to evaluate correlation and agreement of 1,25(OH)2 vitD measurements between the two immunoassays and with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Results: Total imprecision was 5.2% or less for the DiaSorin test but reached 20.1% for the IDS iSYS test. 1,25(OH)2 vitD concentrations measured with the DiaSorin assay showed a strong correlation with 1,25(OH)2 vitD levels measured by LC-MS/MS and a good agreement with method specific means of DEQAS samples. By contrast, the IDS iSYS test overestimated 1,25(OH)2 vitD concentrations in human serum, particularly at higher concentrations. Conclusions: Due to its high sensitivity, low imprecision, broad measurement range, and good agreement with 1,25(OH)2 vitD concentrations measured by LC-MS/MS, the DiaSorin test is a valuable analytical option for the determination of 1,25(OH)2 vitD.