If anyone is considering using a multiplex assay to measure these, please be aware that the technology is untested and many (if not all) kits suffer from calibration problems.
Please see here:
http://www.sciencedirect.com/science/article/pii/S0009912012001725?v=s5
===
Lawrence de Koning, PhD
Research and Clinical Chemistry fellow
Harvard School of Public Health, Department of Nutrition and
Children's Hospital Boston, Department of Laboratory Medicine.
Mailing address:
Children's Hospital Boston
Department of Lab Medicine
FA 715.2
300 Longwood Ave
Boston, MA, 02115
work (HSPH): 617-432-1841
work (Children's): 617-355-3159
fax (HSPH): 617-432-2435
mobile: 617-990-7797