Serum
ug/L
3.9 – 20 ug/L
Folate deficiency is associated with three important disorders.
Macrocytic megaloblastic anaemia
As with vitamin B12 deficiency, the correlation between serum folate level and peripheral blood findings is not close.
Birth defects, particularly neural tube defects
Studies have shown dramatic reduction in birth defects in women taking 400µg folic acid daily, commencing prior to conception. Cardiovascular disease The evidence is circumstantial only and concerns the plasma homocysteine levels which appear to be a graded independent risk factor for cardiovascular disease. When plasma folate is maintained consistently above 2.5 ug/L, using a supplement of 400µg folic acid daily, plasma homocysteine falls to a low plateau.
Causes of low serum folate
Inadequate diet is the commonest cause. Folate comes particularly from green vegetables and is destroyed by cooking. Deficiency is associated with old age, poverty, alcoholism, anorexia, Malabsorption, coeliac disease, tropical sprue, giardiasis, drugs, anticonvulsants, pyrimethamine, methotrexate and others
High folate levels are due to vitamin supplements or a recent meal high in folate. Total body stores in a healthy individual approximate 10mg, enough to last about 6 months if all dietary folate is removed. Recommencement of folate intake restores serum levels in a few days but replenishment and maintenance of body stores requires sustained intake.
Local test
1 day
Can be added on to an existing request up to 32 h following sample receipt
2 months
Specimen Labelling Procedure
8210
