Normal Reference Ranges
Adult
2 - 20 ng/mL
Pediatric
5 - 21 ng/mL
Clinical Significance
Essential for DNA synthesis. Deficiency causes megaloblastic anemia and neural tube defects in pregnancy. Does NOT cause neurologic symptoms (unlike B12).
Causes of High
- Vegetarian/Vegan diet (high in greens)
- Blind loop syndrome (bacterial overgrowth producing folate)
Causes of Low
- Alcoholism
- Malnutrition
- Pregnancy (increased demand)
- Methotrexate/Phenytoin therapy