Folate (Vitamin B9) in Serum or Plasma

Why Is This Test Done?

Your healthcare provider may order a serum folate test to check for deficiencies, especially if you have symptoms like fatigue, weakness, or unusual bleeding. It’s also used in pregnancy to assess risk for neural tube defects in the baby. Folate levels can also be monitored in people with conditions like alcoholism, certain cancers, or medications that affect folate absorption.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if your lab uses a specific protocol. Bring any medications or supplements you’re taking, as they can influence results. Avoid excessive alcohol use 24 hours before testing.

What Happens During the Test?

A blood sample is drawn from a vein in your arm. You may feel a slight pinch, but it’s quick and usually not painful. The sample is then sent to a lab for analysis.

What Are Possible Results?

Results are reported in nanograms per milliliter (ng/mL) or picograms per milliliter (pg/mL), depending on the lab’s method. Low levels may indicate folate deficiency, while high levels could suggest liver disease or certain medications.