TABLE 3.
Nutritional biomarkers measured in NHANES III (1988–1994) and in the continuous NHANES 1999+1
| Survey cycle and nutritional biomarker (number of analytes if >1) | Matrix | Age or population studied | Laboratory method |
| 1999–2002 | |||
| Folate, total (2) | Serum, WB | ≥3 y | BioRad radio assay |
| Folate forms (2) | Surplus serum | ≥60 y | HPLC-electrochemical detection |
| Vitamin B-12 | Serum | ≥3 y | BioRad radio protein binding assay |
| tHcy | Plasma | ≥3 y | Abbott fluorescence polarization immunoassay |
| MMA | Plasma | ≥3 y | GC-MS |
| Ferritin | Serum | ≥1 y | BioRad radioassay |
| sTfR | Surplus serum | Pregnant women | Roche immunoturbidimetry |
| Iron and TIBC (2) | Serum | ≥1 y | Colorimetric assay |
| Protoporphyrin | WB | ≥1 y | Fluorometric assay |
| Vitamin A and retinyl esters (2) | Serum | ≥3 y | HPLC-UV/vis |
| Vitamin E (2) | Serum | ≥3 y | HPLC-UV/vis |
| Carotenoids (6)2 | Serum | ≥3 y | HPLC-UV/vis |
| 25(OH)D2 | Serum | ≥6 y | DiaSorin radioassay |
| Phytoestrogens (6) | Urine | ≥6 y (one-third sample) | HPLC-tandem MS |
| Iodine2 | Urine | ≥6 y (one-third sample) | Inductively coupled plasma mass spectroscopy |
| Selenium3 | Serum | 3–11 y | Atomic absorption spectroscopy |
| 2003–2006 | |||
| Folate, total (2) | Serum, WB | ≥1 y | BioRad radioassay |
| Vitamin B-6 (1 or 2): | Serum | ≥1 y | |
| PLP (2003–2004) | A/C Diagnostics enzymatic assay | ||
| PLP + 4PA (2005–2006) | HPLC-fluorometric detection | ||
| Vitamin B-12 | Serum | ≥1 y | BioRad radioassay |
| tHcy (2003–2004) | Plasma | ≥3 y | Abbott fluorescence polarization immunoassay |
| tHcy (2005–2006) | ≥20 y | ||
| MMA3 | Plasma | ≥3 y | GC-MS |
| Vitamin C | Serum | ≥6 y | HPLC-electrochemical detection |
| Ferritin | Serum | 1–5 y; F: 12–49 y | Roche immunoturbidimetry |
| sTfR | Serum | 1–5 y; F: 12–49 y | Roche immunoturbidimetry |
| Iron and UIBC (2) | Serum | 3–5 y; F: 12–49 y | Beckman colorimetric assay |
| Protoporphyrin | WB | 3–5 y; F: 12–49 y | Fluorometric assay |
| Vitamin A and retinyl esters (2) | Serum | ≥3 y | HPLC-UV/vis |
| Vitamin E (2003–2004) (3) | Serum | ≥3 y | HPLC-UV/vis |
| Vitamin E (2005–2006) (2) | Serum | ≥3 y | HPLC-UV/vis |
| Carotenoids (2003–2004) (11) | Serum | ≥3 y | HPLC-UV/vis |
| Carotenoids (2005–2006) (7) | Serum | ≥3 y | HPLC-UV/vis |
| 25(OH)D | Serum | ≥1 y | DiaSorin RIA |
| FAs (24)3 | Surplus plasma | ≥20 y (fasted) | GC-MS |
| Phytoestrogens (6) | Urine | ≥6 y (one-third sample) | HPLC-tandem MS |
| Iodine | Urine | ≥6 y (one-third sample) | Inductively coupled MS |
| Selenium3 | Serum | ≥40 y | Inductively coupled MS |
| 2007–2010 | |||
| Folate, total (2) | Serum, WB | ≥1 y | Microbiological assay |
| Folate forms (2)3 | Serum | ≥1 y (one-third sample) | HPLC-tandem MS |
| Vitamin B-6 (2) | Serum | ≥1 y | HPLC-fluorescence detection |
| Ferritin | Serum | 1–5 y; F: 12–49 y | Roche immunoturbidimetry |
| sTfR | Serum | 1–5 y; F: 12–49 y | Roche immunoturbidimetry |
| 25(OH)D metabolites (4) | Serum | ≥1 y | HPLC-tandem MS |
| Phytoestrogens (6) | Urine | ≥6 y (one-third sample) | HPLC-tandem MS |
| Caffeine and metabolites (15)2 | Urine | ≥6 y (one-third sample) | HPLC-tandem MS |
| Iodine | Urine | ≥6 y | Inductively coupled MS |
| 2011–2014 | |||
| Folate | WB | ≥1 y | Microbiological assay |
| Folate forms (6) | Serum | ≥1 y | HPLC-tandem MS |
| Vitamin B-12 | Serum | ≥20 y | Roche electrochemiluminescence |
| MMA | Serum | ≥20 y | HPLC-tandem MS |
| 25(OH)D metabolites (4) | Serum | ≥1 y | HPLC-tandem MS |
| FAs (30) | Serum | 1–11 y, ≥12 y (fasted) | GC-MS |
| Caffeine and metabolites (15) | Ferritin | ≥6 y (one-third sample) | HPLC-tandem MS |
| Electrolytes, Na/K/Cl (3)4 | Urine (24-h) | 20–69 y (one-half sample) | Roche ion selective electrode |
| 2015–2016 | |||
| Folate | WB | ≥1 y | Microbiologic assay |
| Folate forms (6) | Serum | ≥1 y | HPLC-tandem MS |
| Ferritin | Serum | 1–5 y; F: 12–49 y | Roche immunoturbidimetry |
| sTfR | Serum | 1–5 y; F: 12–49 y | Roche immunoturbidimetry |
| 25(OH)D metabolites (4) | Serum | ≥1 y | HPLC-tandem MS |
1
MMA, methylmalonic acid; PLP, pyridoxal-5′-phosphate; sTfR, soluble transferrin receptor; tHcy, total homocysteine; TIBC, total iron binding capacity; UIBC, unsaturated iron binding capacity; UV/vis, UV/visible detection; WB, whole blood; 25(OH)D, 25-hydroxyvitamin D; 4PA, 4-pyridoxic acid.
2
Measured during last 2 y only.
3
Measured during first 2 y only.
4
Measured only during 2014.