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