Folate blood test: what it measures and what your result means

Medically reviewed by Dr Lebeth Jacob · 21 October 2026

Quick answer: Folate (vitamin B9) helps your body make healthy red blood cells and is vital for a baby's development in early pregnancy. It's found in green vegetables, beans, chickpeas and fortified foods. A folate blood test shows whether you're getting enough. Low folate can cause tiredness and anaemia, and is usually easy to correct.

What is folate?

Folate is the natural form of vitamin B9 found in food. Folic acid is the man-made form used in supplements and added to some foods, such as breakfast cereals. Your body uses both in the same way.

Your body only stores enough folate for a few months, so you need a regular supply from your diet. The blood test usually measures serum folate, which reflects your recent intake.

Why is folate tested?

  • You feel tired or breathless, or look pale
  • You have a sore, red tongue or mouth ulcers
  • A full blood count showed large red blood cells
  • You're pregnant, planning a pregnancy or breastfeeding
  • You drink alcohol regularly or have a gut condition such as coeliac disease
  • You take a medicine that affects folate, such as methotrexate or some epilepsy medicines

What does a low folate result mean?

Low folate means you're not getting or absorbing enough. Common reasons are:

  • A diet low in green vegetables, beans, fruit and fortified foods
  • Regular or heavy drinking
  • Pregnancy and breastfeeding, when your needs go up
  • Gut conditions such as coeliac disease
  • Some medicines, including methotrexate, some epilepsy medicines and trimethoprim

Low folate and low B12 cause the same kind of anaemia, so they're usually checked together. If B12 is low as well, it needs treating first or at the same time. Taking folic acid alone can hide a B12 problem while nerve damage carries on.

What does a high folate result mean?

A high folate is usually caused by supplements or eating a lot of fortified foods. It isn't harmful in itself.

What can affect your result?

  • A folate-rich meal or folic acid supplement shortly before the test can raise serum folate
  • Follow the fasting instructions for the test you book
  • Alcohol lowers folate

When to see a GP

Your results report shows the laboratory's normal range and flags any result outside it. Speak to your GP if:

  • Your folate is flagged low, especially if B12 is also low or borderline
  • You have symptoms of anaemia, such as tiredness, breathlessness or palpitations
  • You're pregnant or planning a pregnancy and your folate is low (speak to them promptly)

Folic acid in pregnancy

The NHS advises taking 400 micrograms of folic acid a day from before you get pregnant until 12 weeks of pregnancy, to help prevent problems such as spina bifida. Some women need a higher dose on prescription, for example if they have diabetes, a BMI of 30 or more, take epilepsy medicines, or have a family history of these conditions. Ask your GP if this applies to you.

How we test folate

You can have folate tested with a blood sample taken at one of our 250+ partner clinics, or with a finger-prick kit at home. Samples are analysed by a UKAS-accredited laboratory. Results are usually ready in 3–5 working days, with a doctor's comments on every result.

Tests that include folate

Prices for in-clinic tests include your appointment. Compare every test with folate in the biomarker explorer

Frequently asked questions

Is folate the same as folic acid?

Almost. Folate is the natural form in food, and folic acid is the man-made form in supplements and fortified foods. Your body uses both as vitamin B9.

Can low folate be a sign of cancer?

Rarely. Low folate is usually caused by diet, alcohol, pregnancy, gut conditions or medicines. If you also have unexplained weight loss or other new symptoms, see your GP.

What is a normal folate level for a woman?

The range is the same for men and women. Your report flags your result against the laboratory's range. Women who are pregnant or planning a pregnancy should take folic acid whatever their level.

What causes low folate?

Most often a diet low in green vegetables, beans and fortified foods, or regular drinking. Pregnancy, gut conditions and some medicines can also lower it.

How can I raise my folate?

Eat more green vegetables such as broccoli, spinach and sprouts, plus chickpeas, beans, peas and fortified cereals. A GP may prescribe folic acid tablets, usually for about four months, after checking your B12.