Clinical Significance

Folate is an essential vitamin vital to normal cell growth and DNA synthesis. It is present in a wide variety of foods such as dark, leafy vegetables, citrus fruits, yeast, beans, eggs, and milk. It is absorbed by the small intestine and stored in the liver. A folate deficiency can lead to megaloblastic anemia and ultimately to severe neurological problems.

Folate deficiency can be caused by insufficient dietary intake, malabsorption or excessive folate utilization. Excessive utilization occurs very commonly during pregnancy. Alcoholism, hepatitis, or other liver-damaging diseases can also cause excessive folate utilization. Folate levels in both serum and red blood cells are used to assess folate status. The serum folate level is an indicator of recent folate intake. Red blood cell (RBC) folate is the best indicator of long term folate stores. A low RBC folate value can indicate a prolonged folate deficiency.

Folate and vitamin B₁₂ are linked by the reaction pathway for methionine synthesis. A deficiency in either leads to a disruption of this pathway and to similar clinical symptoms. Another consequence of this common metabolic pathway is that a B₁₂ deficiency disrupts the uptake of folate into RBCs. This leads to a low RBC folate value even with adequate folate intake. For the above reasons, it is often necessary to measure both vitamins in a clinical workup. The treatment depends on which vitamin is deficient.

_{Source: Access Folate IFU #A98032, 6/11/15}