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Folic Acid Test


A folic acid test measures the amount of folic acid in the blood.

The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Folate in liquid portion (plasma) of blood 1

3–13 nanograms per milliliter (ng/mL)

7–30 nanomoles per liter (nmol/L) (SI units)


5–21 ng/mL

11–47 nmol/L


Folate in red blood cells 1

140–628 ng/mL

317–1422 nmol/L (SI units)


More than 160 ng/mL

More than 362 nmol/L

High values

  • High levels of folic acid in the blood may mean that you eat a diet rich in folic acid, take vitamins, or take folic acid pills. Consuming more folic acid than the body needs does not cause problems.
  • High folic acid levels can also mean a vitamin B12 deficiency. Body cells need vitamin B12 to use folic acid. So if vitamin B12 levels are very low, folic acid can't be used by the cells, and high levels of it may build up in the blood. But a folic acid test is not a reliable way to test for a vitamin B12 deficiency.

Low values

  • Low folic acid levels can mean you have a problem with your diet, alcohol dependence, or an eating disorder such as anorexia nervosa.
  • Low folic acid levels can also mean you have a problem absorbing or using folic acid, such as a vitamin C deficiency, liver disease, celiac disease, sprue, or Crohn's disease.
  • Low folic acid levels can cause problems for certain people. For example:
    • A pregnant woman needs extra folic acid for her growing baby.
    • People who have hemolytic anemia, a condition that causes the fast destruction of red blood cells, need more folic acid to make more red blood cells.
    • People who have certain conditions, such as kidney failure and some types of cancer, may use up folic acid quickly. They may need their blood to be cleaned using a machine (kidney dialysis).

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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