Biomarker · Vitamins
Folate (vitamin B9)
Folate is a B vitamin needed to make red blood cells and DNA. What a folate blood test shows, causes of deficiency, and its link with anaemia and homocysteine.
Written by LON6EVITY Editorial Team · Last updated
What folate does
Folate is a B vitamin that the body uses to make red blood cells and genetic material. Folic acid is the synthetic form used in supplements and fortified foods.
Deficiency
Low folate can cause a type of anaemia in which red blood cells are larger than normal. Low folate and low vitamin B12 can produce similar blood count changes, so the two are often tested together. Folate is also one of the vitamins involved in keeping homocysteine in check.
Pregnancy
Adequate folate before and during early pregnancy reduces the risk of neural tube defects, which is why folic acid supplements are commonly advised for people who may become pregnant.
Reference ranges
Reference ranges differ between laboratories, units and methods, and depend on age, sex and your overall clinical picture. A single result is not a diagnosis — interpret it with a qualified clinician.
Factors that can affect the result
- Diet
- Alcohol
- Pregnancy
- Some medicines
- Absorption disorders
Questions people commonly ask
- Why test B12 and folate together?
- Both deficiencies can cause similar anaemia, and treating one while missing the other can be harmful.
Related biomarkers
Related tests
Understand your biomarkers in context
What does this mean for your own health data? Log your results, follow trends over time and bring an organised summary to your next doctor's appointment.
Sources
- Homocysteine Test. MedlinePlus, U.S. National Library of Medicine.
- Complete Blood Count (CBC). MedlinePlus, U.S. National Library of Medicine.