Table 1.

Micronutrient Laboratory Biomarkers and Reference Ranges

Micronutrient	Biomarker, analysis method	Units	Plasma or serum	Reference rangesa
B6	Pyridoxal phosphate (PLP), LC/MS/MS	ng/mL	Plasma	2–17 Years	3.0–35.0 ng/mL
				Adult	2.1–21.7 ng/mL
B12	Cobalamin, Immunoassay	pg/mL	Serum	5–9 Years	200–1205 pg/mL
				10–17 years	260–935 pg/mL
				> 17 years	200–1100 pg/mL
Folate	Folate, Immunoassay	ng/mL	Serum	5–9 years	> 7.1 ng/mL
				10–17 years	> 8.0 ng/mL
				≥18 years	> 5.4 ng/mL
Iron (total)	Iron, Spectrophotometry	mcg/dL	Serum	Both sexes
				4–19 years	27–164 mcg/dL
				Male
				20–29 years	50–195 mcg/dL
				≥ 30 years	50–180 mcg/dL
				Female
				20–49 years	40–190 mcg/dL
				≥ 50 years	45–160 mcg/dL

^aQuest Diagnostics