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Methodological issues in assessing plasma 25-hydroxyvitamin D concentration in newborn infants
Sina Gallo1, Kathryn Comeau2, Sherry Agellon2
1Department of Nutrition and Food Studies, George Mason University, Fairfax, VA, USA.
Bone
|January 30, 2014
Summary
Immunoassays for vitamin D (25(OH)D) in infants show significant bias compared to LC-MS/MS, potentially due to metabolite interference. LC-MS/MS is recommended for accurate infant vitamin D status assessment.
Area of Science:
- Clinical Chemistry
- Pediatric Endocrinology
- Vitamin D Metabolism
Background:
- Liquid chromatography tandem mass spectrometry (LC-MS/MS) is a precise method for plasma 25-hydroxyvitamin D (25(OH)D) analysis.
- Immunoassays offer convenience and require small sample volumes, making them suitable for infant testing.
Purpose of the Study:
- To compare the performance of two commercial immunoassays (EIA and RIA) for measuring 25(OH)D in infant plasma against LC-MS/MS.
- To investigate potential interference from other vitamin D metabolites (24,25(OH)(2)D(3) and 3-epi-25(OH)D(3)) in immunoassay results.
Main Methods:
- Analysis of 103 infant capillary blood samples using an enzyme immunoassay (EIA) and a radioimmunoassay (RIA).
- Quantification of plasma 25(OH)D(3), 3-epi-25(OH)D(3), and 24,25(OH)(2)D(3) via LC-MS/MS.
- Spiking experiments with 24,25(OH)(2)D(3) and 3-epi-25(OH)D(3) to assess immunoassay interference.
Main Results:
- Immunoassays yielded significantly different vitamin D status classifications compared to LC-MS/MS.
- Both RIA and EIA showed poor agreement with LC-MS/MS, with notable bias and skew.
- EIA results suggested potential cross-reactivity with 24,25(OH)(2)D(3), but not 3-epi-25(OH)D(3).
Conclusions:
- Commercial immunoassays for infant 25(OH)D measurement can lead to misclassification of vitamin D status due to interference from other metabolites.
- LC-MS/MS is recommended for accurate assessment of vitamin D status in young infants (4-6 weeks).
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