Folate

Background

Folates are compounds of pteroylglutamic acid (PGA) that function as coenzymes in metabolic reactions involving the transfer of single-carbon units from a donor to a recipient compound. Folate, with vitamin B12, is essential for DNA synthesis, which is required for normal red blood cell maturation. Humans obtain Folate from dietary sources including fruits, green and leafy vegetables, yeast, and organ meats. Folate is absorbed through the small intestine and stored in the liver.

Low Folate intake, malabsorption as a result of gastrointestinal diseases, pregnancy, and drugs such as phenytoin are causes of Folate deficiency. Folate deficiency is also associated with chronic alcoholism. Folate and vitamin B12 deficiency impair DNA synthesis, causing macrocytic anemias. These anemias are characterized by abnormal maturation of red blood cell precursors in the bone marrow, the presence of megaloblasts, and decreased red blood cell survival.

Since both Folate and vitamin B12 deficiency can cause macrocytic anemia, appropriate treatment depends on the differential diagnosis of the deficiency. Serum Folate measurement provides an early index of Folate status. However, Folate is much more concentrated in red blood cells than in serum so the red blood cell Folate measurement more closely reflects tissue stores. Red blood cell Folate concentration is considered the most reliable indicator of Folate Status.

Reference ranges

Reference Range: 1.5 – 20.0 ug/L

Specimen requirements

Sample type

• Serum

Sample identification:

• Three patient identifiers from
  • Name
  • D.O.B.
  • Address
  • N.H.S. number
  • Unit Number
  should match on the specimen and request form. This check may be performed prior to centrifugation by the Central Sort department.

Turnaround time

6 hours