Folate Levels Explained: Normal Range & What High Folate Means
Also known as: Vitamin B9, serum folate, folate blood test, folic acid level
Folate (vitamin B9) is a nutrient your body needs to make and repair DNA and produce healthy red blood cells, and a blood test measures how much is circulating. A normal serum folate level is roughly 2.7–17 ng/mL, though this varies by lab and testing method. High folate is usually harmless and comes from supplements or fortified foods, though it can mask an underlying vitamin B12 deficiency, while low folate can cause a type of anemia and is linked to certain birth defects if low during pregnancy. Reference ranges vary by lab, and results are interpreted by a clinician alongside your B12 level and complete blood count.
Folate normal range
| Category | Range (ng/mL) |
|---|---|
| Normal | ~2.7–17 ng/mLReference ranges vary by lab and method |
| Low | < 2.7 ng/mL |
| High | > 17 ng/mLUsually from supplements or fortified foods |
Reference ranges vary by laboratory. Use the range printed on your own report as the definitive comparison.
What high Folate can mean
- Taking folic acid supplements or a multivitamin
- Eating a lot of fortified foods (cereals, bread, pasta)
- Can mask an underlying vitamin B12 deficiency, so B12 is usually checked alongside folate
What low Folate can mean
- Inadequate dietary intake of folate-rich foods
- Alcohol use, which impairs folate absorption and storage
- Malabsorption conditions such as celiac disease
- Increased need during pregnancy
- Certain medications, including some anti-seizure and chemotherapy drugs
What to do about an abnormal result
- Compare your value to the reference range on your own report — folate assays and cutoffs vary by lab.
- Low folate is treated with dietary changes or supplements and is usually checked alongside vitamin B12 to rule out a combined deficiency.
- High folate from diet or supplements is generally not harmful, but tell your doctor about your supplement use so they can interpret your B12 level correctly.
- Don't self-diagnose from one number — folate is interpreted alongside B12, your complete blood count, and MCV by a clinician.
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Frequently asked questions
What does a high folate level mean?
High folate is usually not dangerous and most often comes from folic acid supplements, a multivitamin, or eating a lot of fortified foods like cereal and bread. The main concern is that high folate can mask the blood-count changes of a vitamin B12 deficiency, so doctors typically check B12 alongside folate rather than treating a high folate result on its own.
Is high folate something to worry about?
In most cases, a high folate level simply reflects supplement or dietary intake and isn't harmful by itself. The main reason it matters clinically is that it can hide an underlying B12 deficiency, so your doctor will usually want your B12 level checked as well, especially if you have any nerve-related symptoms like numbness or tingling.
What is a normal folate level?
A normal serum folate level is roughly 2.7 to 17 ng/mL, though the exact cutoffs vary by lab and testing method. Levels below that range suggest folate deficiency, which can cause a type of anemia, while levels above it are usually from supplements or fortified foods.
Related biomarkers
See also
Medically reviewed by Antonieta Rueda, MD and Kyle R. Toth, MD · Last reviewed July 6, 2026
This article is for informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or your lab results.