Folic Acid - Test, Medical Tests, NE - CHI Health, Omaha
Back to MainBack to Main   Print This Page Print    Email to a Friend Email

Folic acid - test


Folic acid is a type of B vitamin. This article discusses the test to measure the amount of folic acid in the blood.

Alternative Names

Folate - test

How the Test is Performed

Most of the time, blood is taken from a vein on the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

How to Prepare for the Test

You should not eat or drink for 6 hours before the test. Your provider may tell you to stop taking any drugs that may interfere with test results, including folic acid supplements.

Drugs that can decrease folic acid measurements include:

  • Alcohol
  • Aminosalicylic acid
  • Birth control pills
  • Estrogens
  • Tetracyclines
  • Ampicillin
  • Chloramphenicol
  • Erythromycin
  • Methotrexate
  • Penicillin
  • Aminopterin
  • Phenobarbital
  • Phenytoin
  • Drugs to treat malaria

How the Test will Feel

You may feel slight pain or a little sting when the needle is inserted. There may be some throbbing at the site.

Why the Test is Performed

This test is done to check for folic acid deficiency.

Folic acid helps form red blood cells and produce DNA that stores genetic codes. Taking the right amount of folic acid before and during pregnancy helps prevent neural tube defects, such as spina bifida.

Women who are pregnant or planning to become pregnant should take at least 600 micrograms (mcg) of folic acid every day. Some women may need to take more if they have a history of neural tube defects in earlier pregnancies. Ask your provider how much you need.

Normal Results

The normal range is 2.7 to 17.0 nanograms per milliliter (ng/mL).

Note: Normal value ranges may vary slightly among different labs. Talk to your health care provider about the meaning of your test results.

The examples above show the common measurements for results for these tests. Some labs use different measurements or may test different specimens.

What Abnormal Results Mean

Lower-than-normal folic acid levels may indicate:

The test may also be done in cases of:


There is very little risk involved with having your blood taken.

Other slight risks from having blood drawn may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)


Antony AC. Megaloblastic Anemias. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 32.

Elghetany MT, Banki K. Erthrocytic Disorders. In: Mcpherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 32.

Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 225.

Review Date: 2/5/2015
Reviewed By: Emily Wax, RD, The Brooklyn Hospital Center, Brooklyn, NY. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.