Folic acid is a member of the "B" vitamin family and is water-soluble. The test is usually run on serum in conjunction with B12. It is necessary for new cell growth, especially the lining of the G.I. tract, the surface of the tongue and in pregnancy. It helps mobilize fat from the liver, and is necessary for the synthesis of red and white blood cells. It serves as a precursor for nucleic acids and as a repair mechanism for DNA. It serves as a methyl donor and helps convert homocysteine back to methionine. Decreased levels can cause anemia (megaloblastic anemia), growth problems, birth defects (spinal bifida), fatigue, poor memory (Alzheimer's disease), sore tongue, digestive problems, toxemia of pregnancy, and an increased risk for strokes and heart attacks. Folate is found in liver, salmon, eggs, whole wheat, asparagus, and green leafy vegetables. It is added to all cereal grains. The RDA is 400 micrograms. A suggested supplemental level is 400 to 2000 micrograms. There is no toxic dose listed for folic acid.