K Aaron Geno 1 , Nicole V Tolan 2 , Ravinder J Singh 3 , Robert D Nerenz 1 Show Affiliations »
Abstract
BACKGROUND: Despite recommendations to limit vitamin D testing to specific clinical scenarios, test volume remains high in many clinical laboratories. Automated total vitamin D immunoassays frequently under- or over-recover 25-hydroxyvitamin D2 [25(OH)D2], making accurate assessment of vitamin D status difficult in patients taking high-dose 25(OH)D2 supplements. Mass spectrometry-based methods offer excellent recovery of 25(OH)D2 but are not practical for use in all laboratories. In this study, we evaluated 2 automated immunoassays against an LC-MS/MS method performed at a national reference laboratory. METHODS: A method comparison against LC-MS/MS was performed for the Roche Elecsys Vitamin D total II assay and the IDS-iSYS 25 VitDS immunoassays using 49 patient specimens submitted for clinical 25(OH)D measurement. Mean bias was calculated, and vitamin D status was determined for each specimen according to the 2011 Endocrine Society clinical practice guidelines. RESULTS: Theil-Sen regression lines relative to LC-MS/MS were y = 0.88x + 2.94 for Roche and y = 1.03x + 2.48 for IDS. Mean bias (±SD) in samples with 25(OH)D2 concentrations less than 5 ng/mL was -0.25 ng/mL (±6.30) for Roche and -1.45 ng/mL (±6.82) for the IDS. Mean bias (±SD) in samples with 25(OH)D2 concentrations greater than 5 ng/mL was -3.19 ng/mL (±6.61) for Roche and 5.52 ng/mL (±6.36) for IDS. Median percentage recovery of 25(OH)D2 was 87.1% (interquartile range 76.0-111.3) for Roche and 120.6% (interquartile range: 105.3-133.4) for IDS. Vitamin D status was misclassified in 7 samples by the Roche assay and 3 by the IDS assay. For all but one of the discordant pairs, the immunoassay result was within 1.7 ng/mL of the diagnostic cutoff. CONCLUSIONS: The automated immunoassays evaluated here demonstrate improved recovery of 25(OH)D2 relative to previous generations. Both are acceptable for use in the determination of vitamin D status. © American Association for Clinical Chemistry 2020. All rights reserved. For permissions, please email: journals.permissions@oup.com.
BACKGROUND: Despite recommendations to limit vitamin D testing to specific clinical scenarios, test volume remains high in many clinical laboratories. Automated total vitamin D immunoassays frequently under- or over-recover 25-hydroxyvitamin D2 [25(OH)D2 ], making accurate assessment of vitamin D status difficult in patients taking high-dose 25(OH)D2 supplements. Mass spectrometry-based methods offer excellent recovery of 25(OH)D2 but are not practical for use in all laboratories. In this study, we evaluated 2 automated immunoassays against an LC-MS/MS method performed at a national reference laboratory. METHODS: A method comparison against LC-MS/MS was performed for the Roche Elecsys Vitamin D total II assay and the IDS -iSYS 25 VitDS immunoassays using 49 patient specimens submitted for clinical 25(OH)D measurement. Mean bias was calculated, and vitamin D status was determined for each specimen according to the 2011 Endocrine Society clinical practice guidelines. RESULTS: Theil-Sen regression lines relative to LC-MS/MS were y = 0.88x + 2.94 for Roche and y = 1.03x + 2.48 for IDS . Mean bias (±SD) in samples with 25(OH)D2 concentrations less than 5 ng/mL was -0.25 ng/mL (±6.30) for Roche and -1.45 ng/mL (±6.82) for the IDS . Mean bias (±SD) in samples with 25(OH)D2 concentrations greater than 5 ng/mL was -3.19 ng/mL (±6.61) for Roche and 5.52 ng/mL (±6.36) for IDS . Median percentage recovery of 25(OH)D2 was 87.1% (interquartile range 76.0-111.3) for Roche and 120.6% (interquartile range: 105.3-133.4) for IDS . Vitamin D status was misclassified in 7 samples by the Roche assay and 3 by the IDS assay. For all but one of the discordant pairs, the immunoassay result was within 1.7 ng/mL of the diagnostic cutoff. CONCLUSIONS: The automated immunoassays evaluated here demonstrate improved recovery of 25(OH)D2 relative to previous generations. Both are acceptable for use in the determination of vitamin D status. © American Association for Clinical Chemistry 2020. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Entities: Chemical
Gene
Species
Keywords:
25-hydroxyvitamin D2; 25-hydroxyvitamin D3; immunoassay
Year: 2020
PMID： 32529210 DOI： 10.1093/jalm/jfaa070
Source DB: PubMed Journal: J Appl Lab Med ISSN： 2475-7241