Folate blood test

Overview

A folate blood test measures the level of folate (a B vitamin) in your blood. Folate helps your body make red blood cells and DNA. Low levels can lead to a type of anemia called megaloblastic anemia, where red blood cells are larger than normal and don't work properly.

Folate deficiency is not very common in countries where food is fortified with folic acid, but it can still happen, especially in people with poor diets or certain health conditions.

It can affect anyone, but it is more common in pregnant women, older adults, people who drink a lot of alcohol, and those with conditions that affect how the body absorbs nutrients (like coeliac disease or Crohn's disease).

Symptoms

Common symptoms

• Feeling very tired and weak
• Pale skin
• Shortness of breath
• Feeling dizzy or lightheaded
• Irritability
• Sore, red tongue
• Mouth ulcers

Symptoms in children

• Slow growth and development
• Pale skin and tiredness
• Poor appetite
• Delayed milestones (like walking or talking)

Symptoms in older adults

• Confusion or memory problems
• Fatigue and weakness
• Loss of appetite
• Depression or mood changes

Causes

Main causes

• Not getting enough folate from your diet – especially if you eat few leafy green vegetables, legumes, or fortified grains
• Conditions that prevent your body from absorbing nutrients properly, like coeliac disease, Crohn's disease, or after weight-loss surgery
• Alcohol use disorder – alcohol can lower folate levels and affect absorption
• Pregnancy – folate needs increase during pregnancy
• Certain medicines (talk to your doctor if you take methotrexate, anticonvulsants, or sulfasalazine)

Risk factors

• A diet low in fresh fruits and vegetables
• Heavy alcohol use
• Pregnancy and breastfeeding
• Being older than 65
• Having a digestive disorder that affects absorption
• Taking certain medicines (ask your doctor if any of yours might lower folate)

When to see a doctor

See a doctor urgently if:

• You have severe symptoms such as chest pain, shortness of breath, or a very fast heartbeat
• You feel like you might faint or have fainted

Book a routine appointment if:

• You have been feeling tired, weak, or pale for a few weeks without an obvious reason
• You have a condition that affects nutrient absorption and want to check your folate levels
• You are pregnant or planning to become pregnant

Diagnosis

A folate blood test is a simple blood test. Your doctor will take a sample of blood from a vein in your arm and send it to a lab to measure your folate level. The test usually includes a full blood count and may also check your vitamin B12 level.

Tests that may be done

• Folate blood test (serum folate) – measures the amount of folate in your blood
• Red blood cell folate test – shows how much folate your body has stored over the past few months
• Full blood count (FBC) – to check for anemia and look at the size of your red blood cells
• Vitamin B12 test – often done at the same time because B12 deficiency can cause similar symptoms

What to expect at your appointment

You don't need to do anything special before the test, but your doctor may ask you to fast (not eat or drink anything except water) for a few hours beforehand. The test is quick and involves a small needle stick – you might feel a pinch. Results usually come back within a few days.

Treatment

If your folate level is low, treatment usually involves increasing folate in your diet and taking a supplement (folic acid) under your doctor's guidance. Your doctor will also treat any underlying cause, such as a digestive condition or alcohol use. Most people feel better within a few weeks.

Self-care at home

• Eat more folate-rich foods: leafy green vegetables (spinach, kale, broccoli), legumes (beans, lentils, chickpeas), citrus fruits, and fortified cereals or bread
• Limit alcohol or get help to reduce your drinking
• Cook vegetables lightly – folate can be destroyed by high heat or long cooking times

Medical treatments

Your doctor may recommend a folic acid supplement (tablet) to take daily or weekly until your levels return to normal. Never take more than the amount your doctor advises, because too much can mask a vitamin B12 deficiency. If you have an underlying condition like coeliac disease, you will need to manage that condition too.

When is surgery considered?

Surgery is not used to treat low folate. However, if you have a digestive condition that requires surgery (like weight-loss surgery or removal of part of the small intestine), you will need lifelong monitoring and support for folate and other nutrients.

Living with this condition

Most people with low folate feel better soon after starting treatment. You may need to continue taking a supplement for several months, and your doctor may repeat the blood test to check your levels. If you have a long-term condition that affects absorption, you will likely need regular blood tests and ongoing supplements.

Lifestyle tips

• Build a balanced diet with plenty of folate-rich foods every day
• If you drink alcohol, try to cut back or quit – ask your doctor for support
• Take your supplements exactly as prescribed, and don't stop without talking to your doctor
• Keep a food diary if you think your diet might be low in nutrients

Diet and exercise

Aim for at least five servings of fruits and vegetables each day, including dark leafy greens. Exercise can help your overall energy and mood – start slowly if you feel tired. Walking, stretching, and light activity are good choices until your energy returns.

Mental health and emotional wellbeing

Living with chronic fatigue or anemia can be frustrating and may affect your mood. Feeling drained all the time can also make you feel anxious or down. Remember that this is temporary – treating the deficiency often improves energy and mood. If you feel depressed, talk to your doctor or a mental health professional.

Prevention

Yes, in many cases. Eating a balanced diet with plenty of folate-rich foods is the best way to prevent deficiency. Some people may need extra folic acid, such as women planning pregnancy or those with certain medical conditions. Limiting alcohol also helps reduce risk.

Complications

If left untreated

• Megaloblastic anemia – severe tiredness, shortness of breath, and pale skin
• Nerve damage – numbness, tingling, or burning in the hands and feet
• Increased risk of depression and cognitive decline in older adults
• In pregnancy, folate deficiency can raise the risk of neural tube defects in the baby (like spina bifida)

Long-term outlook

The outlook for folate deficiency is excellent. With proper treatment – dietary changes and supplements – most people recover fully within weeks to months. Serious complications are very rare when the condition is caught early. If you have an underlying condition that caused the deficiency, you will need ongoing care, but a nutritious diet and regular monitoring can keep you healthy.

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