Interlaboratory Comparison of 25-Hydroxyvitamin D Assays: Vitamin D Standardization Program (VDSP) Intercomparison Study 2 – Part 2 Immunoassays – Impact of 25 Hydroxyvitamin D2 and 24R,25-Dihydroxyvitamin D3 on Assay Performance

Published

August 27, 2021

Author(s)

Stephen Wise, Johanna Camara, Carolyn Burdette, Grace Hahm, Federica Nalin, Adam Kuszak, Joyce Merkel, Ramon Durazo-Arvizu, Emma Williams, Christian Popp, Christian Beckert, Jan Schultess, Glen Van Slooten, Carole Tourneur, Camille Pease, Kavi Kaul, Alfredo Villarreal, Marcelo Batista, Heather Pham, Alex Bennett, Eugene Jansen, Dilshad Khan, Mark Kilbane, Patrick Twomey, James Freeman, Neil Parker, Sohail Mushtaq, Christine Simpson, Pierre Lukas, Etienne Cavalier, Christopher Sempos

Abstract

An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of immunoassays (Part 2) for the determination of serum total 25 hydroxyvitamin D [25(OH)D]. A set of 50 single-donor samples was assigned target values for concentrations of 25(OH)D2, 25(OH)D3, and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] using reference measurement procedures (RMPs) based on isotope dilution liquid chromatography – tandem mass spectrometry (ID LC-MS/MS) and for 3-epi-25-hydroxyvitamin D3 [3-epi-25(OH)D3] using a similar ID LC-MS/MS method. VDSP Intercomparison Study 2 Part 2 includes results from 28 laboratories using 32 immunoassays. Assay performance was evaluated using linear regression analysis of the test assay mean results and the NIST target values and using mean % bias compared to the target values. Only 50 % of the immunoassays met the VDSP criterion of mean % bias ≤ ±5 %. For the 13 unique immunoassays evaluated in this study, only 4 assays were consistently within ±5 % mean bias and 4 assays were consistently outside ±5 % mean bias regardless of the laboratory performing the assay; the remaining 6 assays had results both within and outside the ±5 % mean bias depending on the laboratory performing the tests. Based on multivariable regression analysis using the concentrations of the individual vitamin D metabolites in the 50 single-donor samples, most assays underestimate 25(OH)D2 and several assays (Abbott, Biomérieux, DiaSorin, IDS-EIA, and IDS-iSYS) may have cross-reactivity from 24R,25(OH)2D3. The results of this interlaboratory study represents the most comprehensive comparison of immunoassay performance for determination of serum total 25(OH)D published to date and is the only study to assess the impact of 24R,25(OH)2D3 content using results from a RMP.

Citation

Analytical and Bioanalytical Chemistry

Pub Type

Journals

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Keywords

25-hydroxyvitamin D3, 25-hydroxyvitamin D2, total 25-hydroxyvitamin D, 3-epi-25-hydroxyvitamin D3, 24R, 25-dihydroxyvitamin D3, liquid chromatography – tandem mass spectrometry (LC-MS/MS), immunoassay, reference measurement procedure (RMP), Vitamin D Standardization Program (VDSP)

Citation

Wise, S. , Camara, J. , Burdette, C. , Hahm, G. , Nalin, F. , Kuszak, A. , Merkel, J. , Durazo-Arvizu, R. , Williams, E. , Popp, C. , Beckert, C. , Schultess, J. , Van Slooten, G. , Tourneur, C. , Pease, C. , Kaul, K. , Villarreal, A. , Batista, M. , Pham, H. , Bennett, A. , Jansen, E. , Khan, D. , Kilbane, M. , Twomey, P. , Freeman, J. , Parker, N. , Mushtaq, S. , Simpson, C. , Lukas, P. , Cavalier, E. and Sempos, C. (2021), Interlaboratory Comparison of 25-Hydroxyvitamin D Assays: Vitamin D Standardization Program (VDSP) Intercomparison Study 2 – Part 2 Immunoassays – Impact of 25 Hydroxyvitamin D2 and 24R,25-Dihydroxyvitamin D3 on Assay Performance, Analytical and Bioanalytical Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932141 (Accessed April 25, 2024)