Assessment of serum total 25-hydroxyvitamin D assay commutability of Standard Reference Materials and College of American Pathologists Accuracy-Based Vitamin D (ABVD) Scheme and Vitamin D External Quality Assessment Scheme (DEQAS) materials: Vitamin D Standardization Program (VDSP) Commutability Study 2.

Camara, Johanna EWise, Stephen AHoofnagle, Andrew NWilliams, Emma LCarter, Graham DJones, JuliaBurdette, Carolyn QHahm, GraceNalin, FedericaKuszak, Adam JMerkel, JoyceDurazo-Arvizu, Ramón ALukas, PierreCavalier, ÉtiennePopp, ChristianBeckert, ChristianSchultess, JanVan Slooten, GlenTourneur, CarolePease, CamilleKaul, RaviVillarreal, AlfredoIvison, FionaFischer, Ralfvan den Ouweland, Jody M WHo, Chung SLaw, Emmett W KSimard, Jean-NicolasGonthier, RenaudHolmquist, BrettBatista, Marcelo CidadePham, HeatherBennett, AlexMeadows, SarahCox, LornaJansen, EugeneKhan, Dilshad AhmedRobyak, KimberlyCreer, Michael HKilbane, MarkTwomey, Patrick JFreeman, JamesParker, NeilYuan, JinyunFitzgerald, RobertMushtaq, SohailClarke, Michael WBreen, NormaSimpson, ChristineSempos, Christopher T2021-12-232021-12-232021-06-283418410210.1007/s00216-021-03470-whttp://hdl.handle.net/10029/625480An interlaboratory study was conducted through the Vitamin D Standardization Program (VDSP) to assess commutability of Standard Reference Materials® (SRMs) and proficiency testing/external quality assessment (PT/EQA) samples for determination of serum total 25-hydroxyvitamin D [25(OH)D] using ligand binding assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A set of 50 single-donor serum samples were assigned target values for 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3] using reference measurement procedures (RMPs). SRM and PT/EQA samples evaluated included SRM 972a (four levels), SRM 2973, six College of American Pathologists (CAP) Accuracy-Based Vitamin D (ABVD) samples, and nine Vitamin D External Quality Assessment Scheme (DEQAS) samples. Results were received from 28 different laboratories using 20 ligand binding assays and 14 LC-MS/MS methods. Using the test assay results for total serum 25(OH)D (i.e., the sum of 25(OH)D2 and 25(OH)D3) determined for the single-donor samples and the RMP target values, the linear regression and 95% prediction intervals (PIs) were calculated. Using a subset of 42 samples that had concentrations of 25(OH)D2 below 30 nmol/L, one or more of the SRM and PT/EQA samples with high concentrations of 25(OH)D2 were deemed non-commutable using 5 of 11 unique ligand binding assays. SRM 972a (level 4), which has high exogenous concentration of 3-epi-25(OH)D3, was deemed non-commutable for 50% of the LC-MS/MS assays.en© 2021. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.25-Hydroxyvitamin D225-Hydroxyvitamin D3Ligand binding assayLiquid chromatography-tandem mass spectrometry (LC-MS/MS)Total 25-hydroxyvitamin DVitamin D Standardization Program (VDSP)Assessment of serum total 25-hydroxyvitamin D assay commutability of Standard Reference Materials and College of American Pathologists Accuracy-Based Vitamin D (ABVD) Scheme and Vitamin D External Quality Assessment Scheme (DEQAS) materials: Vitamin D Standardization Program (VDSP) Commutability Study 2.Article1618-2650Anal Bioanal Chem 2021 ; 413(20):5067-84