Vitamin B12 level

A blood sample is needed.

You should not eat or drink for about 6 to 8 hours before the test. Certain medicines may affect the results of this test. Your health care provider will tell you if you need to stop taking any medicines. Do not stop any medicine before talking to your provider. Medicines that can affect the test result include:…

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

This test is most often done when other blood tests suggest a condition called megaloblastic anemia. Pernicious anemia causes a form of megaloblastic anemia caused by vitamin B12 deficiency due to poor vitamin B12 absorption. This can occur when the stomach makes less of the substance (called intrinsic factor) the…

Normal values are 160 to 950 picograms per milliliter (pg/mL), or 118 to 701 picomoles per liter (pmol/L). Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your provider about what your specific test results mean.

Values of less than 160 pg/mL (118 pmol/L) are a possible sign of a vitamin B12 deficiency. People with this degree of deficiency are likely to have or develop symptoms. Deficiency should be confirmed by checking the level of a substance in the blood called methylmalonic acid. A high level indicates a true B12…

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others. Other risks associated with having blood drawn are slight, but may include: Excessive…

Marcogliese AN, Hensch L. Resources for the hematologist: interpretive comments and selected reference values for neonatal, pediatric, and adult populations. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 159. Mason JB, Booth…