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Vitamins & Minerals

Folate (Folic Acid)

Folate (vitamin B9) is a B vitamin your body needs to make healthy red blood cells, and it matters most before and during early pregnancy, where getting enough lowers the chance of serious birth defects. A result inside the range on your report means you are unlikely to be short. A low level is common and usually straightforward to put right with your GP's guidance.

Standard Care
CategoryVitamins & Minerals
Reference rangeSee your report
Evidence✓Standard Care
Last updated3 July 2026
On this page
77%

In Australia, the prevalence of low serum folate fell by 77% in the year after mandatory folic acid fortification of bread-making flour was introduced in September 2009.

What is folate (folic acid)?

Folate and its synthetic form folic acid are both names for vitamin B9, a water-soluble B vitamin. Your body needs it to form and repair red blood cells, nerve cells and brain cells, and to build DNA — the genetic blueprint in every cell. Because the body stores folate in smaller quantities than vitamin B12, it must be replenished more regularly through food or supplements. The standard blood test measures serum folate — that is, folate dissolved in the liquid part of your blood (the serum). Serum folate reflects your recent dietary intake over the past few weeks rather than long-term stores. In the past, a test that measured folate stored inside red blood cells (red blood cell folate, or RBC folate) was also used to assess longer-term tissue stores, but red blood cell folate testing is no longer used in routine Australian practice.

Why is it tested?

Folate testing is typically ordered when a Full Blood Count — a routine blood test that checks your red blood cells — shows signs of macrocytic anaemia (anaemia where red blood cells are unusually large). The haematological changes of folate deficiency and vitamin B12 deficiency look identical under the microscope, so both markers are usually tested together to understand the cause. Testing is also common when there is suspected malabsorption (for example, undiagnosed coeliac disease), when someone follows a restrictive diet, if there is a history of alcohol use disorder, or if someone is taking medicines that are known to affect folate metabolism such as anticonvulsants. Serum folate is the usual first-line test. Folate is particularly important in the context of pregnancy planning and early pregnancy. Adequate folate during the weeks around conception — when the neural tube is closing — significantly reduces the risk of neural tube defects (serious birth defects of the brain and spinal cord, such as spina bifida).

Reference range (Australia)

Serum folate: 7–40 nmol/L (deficiency likely below 7). Note: reference intervals vary between laboratories — use the range printed on your report. nmol/L

No sex-specific intervals for serum folate are listed in the Australian Prescriber reference. The interval is assay-dependent and laboratory-specific — the range on your own report is the one that applies to your result.

Reference intervals vary between laboratories. Always use the range printed on your own report.

What your result means

If your level is low

A low serum folate means your level has fallen below the range on your report. Folate responds quickly to what you eat: the Australian Prescriber notes it can drop below normal after only three weeks of falling short, so a low result does not always mean your tissue stores are fully run down. The cause matters most. The common reasons are a low-folate diet (especially few vegetables and grains), trouble absorbing nutrients — for example from coeliac disease, an autoimmune condition that damages the gut lining — alcohol use, and certain medicines. The extra demand of pregnancy can pull levels down too. If your folate is low, your GP looks at the whole picture: your diet, your symptoms, and related markers such as vitamin B12 and your red blood cell indices (MCV and MCH — measures of red blood cell size and haemoglobin content that flag macrocytic anaemia when they are off).

If your level is in range

A result within the reference range on your report means deficiency is unlikely based on your recent dietary intake. Since mandatory folic acid fortification of bread-making flour was introduced in Australia in 2009, most Australians who eat a varied diet including bread maintain adequate serum folate levels. No follow-up for folate is usually needed with a normal result, unless you have specific risk factors your GP is monitoring.

If your level is high

A serum folate above the reference range is generally not a clinical concern and most often reflects recent dietary intake or supplementation — including the folic acid added to bread-making flour since September 2009. It is not usually associated with harm at dietary levels. If you are taking a high-dose supplement, it is worth mentioning to your GP so they can review your routine.

What can affect your result

Diet is the main driver of serum folate. Foods rich in natural folate include leafy green vegetables (spinach, lettuce, asparagus), legumes (lentils, chickpeas), broccoli, and some fruits. Since September 2009, wheat flour used for making bread in Australia has been mandatorily fortified with folic acid — the synthetic form of the vitamin — which has substantially increased population folate intake. Several factors can reduce serum folate: Poor dietary intake is the most common cause. Malabsorption disorders — conditions that interfere with the gut's ability to absorb nutrients — are another important factor. Coeliac disease (an autoimmune condition triggered by gluten) is a key example to exclude. Alcohol use can lower serum folate independently of diet, even without tissue depletion. Certain medicines are recognised causes: anticonvulsants (medicines used to prevent seizures) and drugs such as methotrexate (used in rheumatoid arthritis and some cancer treatments) interfere with folate metabolism. Increased physiological demand also matters. Pregnancy substantially raises the body's folate requirement, and deficiency is more likely if intake does not keep pace.

When to act

If your folate is low and you are planning pregnancy or are in early pregnancy, this is worth raising with your GP promptly — the neural tube closes in the first weeks of pregnancy, often before a pregnancy is confirmed. Your GP can advise on supplementation timing and dose; they may also check vitamin B12 at the same time, since the two vitamins work closely together and a deficiency in one can mask the other. If your folate is low and you are not pregnant, your GP will consider your diet, medications, and gut health to find the most likely cause. They may also check related markers such as MCV, MCH, haemoglobin, and vitamin B12 to build a fuller picture. If your folate is in the normal range and you have no specific risk factors, no action is usually needed. This page is general information and is not a substitute for advice from your GP.

Frequently asked questions

In Australia, serum folate is measured in nmol/L. The Australian Prescriber gives a reference range of 7–40 nmol/L for serum folate, while noting that reference ranges are specific to the laboratory and methodology used. The range printed on your own report is the one your result is compared against, and your GP reads it alongside your diet, symptoms, and any other relevant test results.

Folate plays a critical role in the earliest weeks of pregnancy, when the neural tube — the structure that develops into the brain and spinal cord — is forming and closing. Inadequate folate at this stage is associated with neural tube defects such as spina bifida (incomplete closure of the spine) and anencephaly (incomplete development of the brain). In Australia, between 300 and 350 pregnancies were estimated to be affected by neural tube defects each year before mandatory fortification was introduced. Because the neural tube closes before most women know they are pregnant, the NHMRC recommends that women planning a pregnancy take additional folic acid before conception and in early pregnancy. If you are planning a pregnancy or have just found out you are pregnant, a chat with your GP about folate is well worthwhile.

Mandatory folic acid fortification of wheat flour for making bread has been in place in Australia since September 2009, and it has made a real difference — research found a 77% fall in the prevalence of low serum folate in the first year after fortification was introduced. For most people who eat bread and a reasonably varied diet, fortified flour contributes meaningfully to folate intake. However, fortification was designed to increase population-level intake, not to cover the higher needs of early pregnancy. Women planning a pregnancy are still advised to take a separate folic acid supplement — your GP can confirm the right dose and timing for your situation.

Yes. Folate deficiency can cause macrocytic anaemia — a type of anaemia (low red blood cell count or haemoglobin) where the red blood cells that are produced are unusually large (macrocytic means "large cell"). This happens because folate is needed to divide cells normally; without enough of it, red blood cell production slows and the cells that do form are enlarged. The haematological changes look identical to those caused by vitamin B12 deficiency, which is why both are usually tested together when macrocytic anaemia is found. Left untreated, deficiency of folate or B12 can lead to severe anaemia. Your GP can work out which is the cause and what to do about it.

Several medicines can interfere with how your body absorbs or uses folate. Anticonvulsants — medicines used to control seizures, such as phenytoin or valproate — are a recognised cause of lower folate levels, and testing is sometimes ordered specifically for people taking these drugs long term. Methotrexate (used in rheumatoid arthritis, psoriasis, and some cancer treatments) works partly by blocking folate pathways, which is why folic acid supplementation is often prescribed alongside it. Alcohol can also reduce serum folate quickly, even before tissue stores are affected. If you take any of these medicines regularly and your folate is low, your GP can advise whether monitoring or supplementation is appropriate for you.

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