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Vitamin B9

Vitamins Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Vitamins

Overview

Vitamin B9 (folate) is a water‑soluble B‑vitamin required for DNA synthesis, cell division and methylation reactions. The laboratory folate test measures circulating folate (usually serum/plasma) and sometimes red blood cell (RBC) folate to assess recent intake and longer‑term stores. Low folate suggests deficiency that can cause megaloblastic anemia, glossitis, fatigue, and in pregnancy increased risk of neural tube defects in the fetus. High values usually reflect supplementation or recent dietary intake. Levels vary with age, pregnancy (higher requirement), nutritional status, alcohol use, certain medications, and conditions causing malabsorption; RBC folate is less affected by short‑term dietary changes and better reflects tissue stores.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Which profile: included in vitamin/nutritional deficiency panels (Vitamins).
Symptoms: unexplained anemia, fatigue, pallor, shortness of breath, neuropathy, cognitive changes, or in preconception/pregnancy screening.
Conditions: diagnoses/monitors folate deficiency, megaloblastic anemia, nutritional status in malabsorption, and pregnancy risk assessment.
Reasons for abnormal levels: poor diet, malabsorption (celiac, IBD), alcoholism, increased requirement in pregnancy, or supplementation/hemolysis.
Biological meaning: low values indicate impaired DNA synthesis and cell maturation; high values usually reflect recent intake or supplementation and can mask B12 deficiency.
Behaviors/family history: restrictive diets, heavy alcohol use, long‑term antiepileptic or methotrexate therapy, family history of neural tube defects or metabolic/folate‑metabolism disorders suggest testing.

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Understanding Test Results

Serum folate <3 ng/mL (<6.8 nmol/L) indicates folate deficiency and high risk for megaloblastic anemia, poor cell replication and, in pregnant women, increased neural tube defect risk.
Levels 3–6 ng/mL (6.8–13.6 nmol/L) are often considered low/insufficient and warrant dietary review, medication check and possible repeat or RBC folate measurement.
Values 6–20 ng/mL (13.6–45.3 nmol/L) are generally adequate.
Levels >20 ng/mL (>45.3 nmol/L) usually reflect recent supplementation or hemolysis; very high folate can mask hematologic signs of vitamin B12 deficiency and allow neurologic B12 injury to progress undetected.
RBC folate <140 ng/mL (when reported) indicates depleted tissue stores and chronic deficiency; higher RBC folate denotes repletion.
Clinical correlation and assessment of B12 status is essential for abnormal results.

Normal Range

3-20 ng/mL OR 6.8-45.3 nmol/L

FAQs

Q: What is vitamin B9 called?

A: Vitamin B9 is called folate (the natural form) and folic acid (the synthetic form used in supplements and fortified foods). It is a water soluble B vitamin essential for DNA synthesis, cell division, and red blood cell formation. Adequate intake before and during early pregnancy helps prevent neural tube defects. Good sources include leafy greens, legumes, citrus fruits, and fortified grains.

Q: Which food has vitamin B9?

A: Foods rich in vitamin B9 (folate) include dark leafy greens (spinach, kale), legumes (lentils, chickpeas, beans), asparagus, Brussels sprouts, broccoli, liver, avocado, citrus fruits (oranges), and fortified cereals/grains. Nuts and seeds (including sunflower seeds) also supply folate. Eating a variety of these helps meet daily folate requirements, especially during pregnancy and for healthy red blood cell production.

Q: What are the 5 major functions of vitamin B9?

A: Vitamin B9 (folate) functions include: 1) DNA synthesis and repair; 2) supporting cell division and growth, especially during pregnancy for fetal neural tube development; 3) red blood cell production and prevention of megaloblastic anemia; 4) amino acid metabolism, notably remethylation of homocysteine to methionine; 5) supporting cardiovascular health by helping maintain normal homocysteine levels.

Q: Is folic acid B9 or b6?

A: Folic acid is vitamin B9, not B6. Folic acid is the synthetic form of folate used in supplements and fortified foods; folate (vitamin B9) supports DNA synthesis, red blood cell formation, and fetal neural tube development. Vitamin B6 (pyridoxine) is a different B vitamin involved in amino acid metabolism, neurotransmitter production, and hemoglobin synthesis.

Q: What is vitamin B9 deficiency also known as?

A: Vitamin B9 deficiency is also known as folate deficiency or folic acid deficiency. It commonly causes megaloblastic anemia and, in pregnancy, raises the risk of neural tube defects. Symptoms include fatigue, weakness, pallor, shortness of breath and mouth sores. Causes include poor diet, malabsorption, certain medications and increased demand during pregnancy. Treatment is dietary folate and supplementation.

Q: What foods cause high homocysteine levels?

A: Foods high in methionine especially red and processed meats, organ meats, eggs, some dairy and seafood can raise homocysteine. Diets low in folate, vitamin B6 and B12 (too few leafy greens, legumes, nuts and fortified cereals) also promote elevated levels. Excessive alcohol and heavy coffee intake may further increase homocysteine.