Table 1

Micronutrient assay methods.

Analyte
Method
Ref.

RBC folate (nmol/L)
Quantaphase Folate Radioassay Kit, Bio-Rad Laboratories
7
Retinol (μg/dL)
Isocratic reversed-phase HPLC with UV/Vis detection
8
Ascorbic acid (mg/dL)
Isocratic reversed-phase HPLC with Electrochemical detection*
7
Alpha tocopherol (mg/dL)
Isocratic reversed-phase HPLC with UV/Vis detection
8
Alpha carotene (μg/dL)
Isocratic reversed-phase HPLC with UV/Vis detection
8
Beta carotene (μg/dL)
Isocratic reversed-phase HPLC with UV/Vis detection
8
Ferritin (μg/L)
Quantlmune Ferritin IRMA kit, Bio-Rad Laboratories
7
25-hydroxyvitamin D (nmol/L)
Quantlmune Ferritin IRMA kit, Bio-Rad Laboratories
7
Homocysteine (μmol/L)
Isocratic reversed-phase HPLC with Fluorescence detection
9
C-reactive protein (mg/L)
Latex-enhanced nephelometry, Behring Nephelometer Analyzer for NHANES assays and Hitachi 917 Analyzer for Multiple Supp user assays
7
Total cholesterol (mg/dL)
Timed endpoint, coupled enzymatic methodology
10
LDL-cholesterol (mg/dL)
Calculated**
7
HDL-cholesterol (mg/dL)
Polyanion/divalent cation precipitation of other lipoproteins followed by timed endpoint, coupled enzymatic methodology
10
Triglycerides (mg/dL)
Timed endpoint, coupled enzymatic methodology
11

*Use of 1 part serum plus 1 part 10% meta-phosphoric acid for Multiple Supp users versus NHANES use of 1 part serum plus 4 part meta-phosphoric acid.

** Calculated: LDL-cholesterol = [total cholesterol - HDL-cholesterol - (triglycerides/5)] Ref = reference, LDL = low-density lipoprotein, HDL = high-density lipoprotein.

Block et al. Nutrition Journal 2007 6:30   doi:10.1186/1475-2891-6-30