Competitive chemiluminescent enzyme immunoassay for vitamin B12 analysis in human milk

Daniela Hampel; Setareh Shahab-Ferdows; Joseph M Domek; Towfida Siddiqua; Rubhana Raqib; Lindsay H Allen

doi:10.1016/j.foodchem.2013.12.033

Competitive chemiluminescent enzyme immunoassay for vitamin B12 analysis in human milk

Food Chem. 2014 Jun 15:153:60-5. doi: 10.1016/j.foodchem.2013.12.033. Epub 2013 Dec 14.

Authors

Daniela Hampel¹, Setareh Shahab-Ferdows², Joseph M Domek², Towfida Siddiqua³, Rubhana Raqib⁴, Lindsay H Allen⁵

Affiliations

¹ USDA, ARS Western Human Nutrition Research Center, 430 W. Health Sciences Drive, Davis, CA 95616, USA; Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA. Electronic address: daniela.hampel@ars.usda.gov.
² USDA, ARS Western Human Nutrition Research Center, 430 W. Health Sciences Drive, Davis, CA 95616, USA.
³ USDA, ARS Western Human Nutrition Research Center, 430 W. Health Sciences Drive, Davis, CA 95616, USA; Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; International Centre for Diarrheal Disease Research, Dhaka, Bangladesh.
⁴ International Centre for Diarrheal Disease Research, Dhaka, Bangladesh.
⁵ USDA, ARS Western Human Nutrition Research Center, 430 W. Health Sciences Drive, Davis, CA 95616, USA; Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA.

PMID: 24491700
DOI: 10.1016/j.foodchem.2013.12.033

Abstract

Recent discoveries of matrix interferences by haptocorrin (HC) in human milk and serum show that past analyses of vitamin B12 in samples with high HC content might have been inaccurate (Lildballe et al., 2009; Carmel & Agrawal, 2012). We evaluated two competitive enzyme-binding immunoassays for serum/plasma (IMMULITE and SimulTRAC-SNB) for B12 analysis in human milk. B12-recovery rates (United States Environmental Protection Agency, 2007) were determined to be 78.9 ± 9.1% with IMMULITE and 225 ± 108% (range 116-553%) using SimulTRAC-SNB, most likely due to the presence of excess HC. HC-interferences were not observed with the IMMULITE assay, rendering previously reported mandatory HC-removal (Lildballe et al., 2009) unnecessary. Linearity continued at low B12-concentrations (24-193 pM; r(2)>0.985). Milk B12 concentrations from Bangladeshi women (72-959 pM) were significantly lower than those from California (154-933 pM; p<0.0001) showing IMMULITE's robustness against the complex milk matrix and its ability to measure low milk B12 concentrations.

Keywords: Chemiluminescence; Cobalamin; Haptocorrin; Human milk; Radioassay; Vitamin B12.

Publication types

Evaluation Study
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Adult
Female
Humans
Immunoenzyme Techniques / methods*
Luminescent Measurements / methods*
Milk, Human / chemistry*
Vitamin B 12 / analysis*

Substances

Vitamin B 12