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Normal vitamin B9 (folic acid) level in the blood

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Normal vitamin B9 (folic acid) level in the blood
Last update: 13/05/2022

What is the normal level of vitamin B9 in the blood?

The normal range for vitamin B9 (folic acid) in the blood is age-dependent:

Adults: 3–20 ng/mL
Children: 5–21 ng/mL
Infant: 14–51 ng/mL

In the International System of Units (SI), vitamin B9 (folic acid) in the blood is measured in nmol/L. The normal vitamin B9 (folic acid) level in the blood in the SI is:

Adults: 6.8–45.3 nmol/L
Children: 11.3–47.6 nmol/L
Infant: 31.7–115.5 nmol/L

Why normal levels can differ across different labs?

Each laboratory must establish its own normal ranges for vitamin B9 (folic acid) in the blood. These ranges depend on the makeup of the local population, the technologies used and the accuracy of the measurement. There may be also slight differences in the normal levels, according to age, gender, race or ethnic origin, geographic region, diet, type of sample and other relevant status.

Your doctor will study the results along with your medical record, screenings, physical condition, symptoms and any other relevant information about your situation.

In elderly people, the average normal range is usually lower.

There is also another test called RBC (Red Blood Cell) folate concentration that measures the folate in RBCs instead of in the blood. The previous levels are for folates (vitamin B9) in the blood. The normal range for RBC (Red Blood Cell) folate concentration is 125 to 600 ng/ml.

What is the role of vitamin B9 in the body?

Vitamin B9 is also known as folate or folic acid. Both terms are forms of vitamin B9. Folates are naturally present in food, whereas folic acid is a synthetic type of folate.

Vitamin B9 is required for RBCs (Red Blood Cell) production and WBCs (White Blood Cell) formation. It is also important for brain health and cell division. If there is a vitamin B9 deficiency, there will be not enough amount of RBCs (red blood cells) and anemia will develop.

Folates are absorbed from the diet in the small intestine (jejunum) and the excess of folates are excreted through the urine.

Folates are present in a wide variety of foods, including green leafy vegetables (spinach, lettuce, cabbage, broccoli, etc.), asparagus, fruits (citrus, kiwi, etc.), milk and animal liver or kidney.

Vitamin B9 is especially needed during pregnancy for the developing fetus. Deficiency of this type of vitamin can lead to neural tube defects, so pregnant women are advised to consume acid folic supplements.

What is the vitamin B9 blood test used for?

Vitamin B9 (folic acid) blood test is performed in case of macrocytic anemia, a type of anemia where there is a low level of hemoglobin in the blood with large RBCs (Red Blood Cells).

Vitamin B9 blood test may give useful information about this type of anemia. Macrocytic anemia is characterized by:

  • Anemia (low level of hemoglobin in the blood)
  • Macrocytosis or high MCV (greater than 100 fl.)

Levels of folate (vitamin B9) and vitamin B12 (cobalamin) are usually tested in conjunction with one another because the diagnosis of macrocytic anemia requires measurement of both to discern the underlying cause.

This test is also used to monitor therapy for low folate in the blood.

Where can I find more information about vitamin B9 in a blood test?

You can visit our pages about:

Which values are considered a normal vitamin B9 in a blood test?

The following values are considered to be normal values:

IMPORTANT: These levels are expressed in ng/ml. They are an example of a healthy adult of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.

Vitamin B9 (Folic Acid)
Normality
3 ng/ml3.1 ng/ml3.2 ng/ml3.3 ng/ml3.4 ng/ml3.5 ng/ml3.6 ng/ml3.7 ng/ml
3.8 ng/ml3.9 ng/ml4 ng/ml4.1 ng/ml4.2 ng/ml4.3 ng/ml4.4 ng/ml4.5 ng/ml
4.6 ng/ml4.7 ng/ml4.8 ng/ml4.9 ng/ml5 ng/ml5.1 ng/ml5.2 ng/ml5.3 ng/ml
5.4 ng/ml5.5 ng/ml5.6 ng/ml5.7 ng/ml5.8 ng/ml5.9 ng/ml6 ng/ml6.1 ng/ml
6.2 ng/ml6.3 ng/ml6.4 ng/ml6.5 ng/ml6.6 ng/ml6.7 ng/ml6.8 ng/ml6.9 ng/ml
7 ng/ml7.1 ng/ml7.2 ng/ml7.3 ng/ml7.4 ng/ml7.5 ng/ml7.6 ng/ml7.7 ng/ml
7.8 ng/ml7.9 ng/ml8 ng/ml8.1 ng/ml8.2 ng/ml8.3 ng/ml8.4 ng/ml8.5 ng/ml
8.6 ng/ml8.7 ng/ml8.8 ng/ml8.9 ng/ml9 ng/ml9.1 ng/ml9.2 ng/ml9.3 ng/ml
9.4 ng/ml9.5 ng/ml9.6 ng/ml9.7 ng/ml9.8 ng/ml9.9 ng/ml10 ng/ml10.1 ng/ml
10.2 ng/ml10.3 ng/ml10.4 ng/ml10.5 ng/ml10.6 ng/ml10.7 ng/ml10.8 ng/ml10.9 ng/ml
11 ng/ml11.1 ng/ml11.2 ng/ml11.3 ng/ml11.4 ng/ml11.5 ng/ml11.6 ng/ml11.7 ng/ml
11.8 ng/ml11.9 ng/ml12 ng/ml12.1 ng/ml12.2 ng/ml12.3 ng/ml12.4 ng/ml12.5 ng/ml
12.6 ng/ml12.7 ng/ml12.8 ng/ml12.9 ng/ml13 ng/ml13.1 ng/ml13.2 ng/ml13.3 ng/ml
13.4 ng/ml13.5 ng/ml13.6 ng/ml13.7 ng/ml13.8 ng/ml13.9 ng/ml14 ng/ml14.1 ng/ml
14.2 ng/ml14.3 ng/ml14.4 ng/ml14.5 ng/ml14.6 ng/ml14.7 ng/ml14.8 ng/ml14.9 ng/ml
15 ng/ml15.1 ng/ml15.2 ng/ml15.3 ng/ml15.4 ng/ml15.5 ng/ml15.6 ng/ml15.7 ng/ml
15.8 ng/ml15.9 ng/ml16 ng/ml16.1 ng/ml16.2 ng/ml16.3 ng/ml16.4 ng/ml16.5 ng/ml
16.6 ng/ml16.7 ng/ml16.8 ng/ml16.9 ng/ml17 ng/ml17.1 ng/ml17.2 ng/ml17.3 ng/ml
17.4 ng/ml17.5 ng/ml17.6 ng/ml17.7 ng/ml17.8 ng/ml17.9 ng/ml18 ng/ml18.1 ng/ml
18.2 ng/ml18.3 ng/ml18.4 ng/ml18.5 ng/ml18.6 ng/ml18.7 ng/ml18.8 ng/ml18.9 ng/ml
19 ng/ml19.1 ng/ml19.2 ng/ml19.3 ng/ml19.4 ng/ml19.5 ng/ml19.6 ng/ml19.7 ng/ml
19.8 ng/ml19.9 ng/ml20 ng/ml     
Medically reviewed by our Medical staff on 13/05/2022

Bibliography

  • Concise Book of Medical Laboratory Technology: Methods and Interpretations. 2nd Edition. 2015. Ramnik Sood. ISBN: 978-93-5152-333-8. Pag. 251.
  • Hematology. Basic principles and practice 7th edition. Ronald Hoffman, Edward J. Benz Jr, Leslie E. Silberstein, Helen E. Heslop, Jeffrey I. Weitz, John Anastasi, Mohamed E. Salama, Syed Ali Abutalib. chapter73, Pag 518. 2018. ISBN: 978-0-323-35762-3.
  • A Manual of Laboratory and Diagnostic Test. 9th edition. Frances Fischbach. Marshall B. Dunning III. 2014. Pag 136. ISBN-10: 1451190891.
  • Laboratory tests and diagnostic procedures with nursing diagnoses (8th ed), Jane Vincent Corbett, Angela Denise Banks, ISBN: 978-0-13-237332-6, Pag. 37.
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