This test is used to determine folic acid (folate) levels. Folic acid (Folate) is a B vitamin that plays an important role in DNA synthesis and producing red blood cells. Folic acid is absorbed through the small intestine and stored in the liver and must be ingested through diet since it cannot be made by the body itself. This blood test is used to detect a folic acid deficiency, monitor therapy with folic acid, and/or evaluate megaloblastic and macrocytic anemia. Deficiencies in folic acid can cause neural tube defects to occur to a fetus during pregnancy.