Folate (Vitamin B9) Blood Test
Folate, also known as vitamin B9, is a water-soluble vitamin that must come from your diet. It plays a central role in DNA synthesis, tissue repair and red blood cell production. Together with vitamins B12 and B6, folate keeps homocysteine levels in check and supports methylation processes throughout the body. Deficiency is particularly dangerous during pregnancy, when it can cause neural tube defects in the developing baby. Blood levels decline after just a few weeks on a low-folate diet, making regular testing valuable.
Why Test Folate?
A folate test is relevant if you are pregnant or planning to conceive, if you eat few fruits and vegetables, smoke, drink excessively, or have a condition that impairs absorption such as celiac disease or IBD. Certain medications also increase your need for folate. Testing helps ensure adequate levels for cellular health and homocysteine regulation.
What Do High Folate Levels Mean?
High serum folate usually reflects generous intake of fortified foods or supplements and is generally not harmful. However, excess folate can mask a vitamin B12 deficiency by correcting the anaemia it causes while allowing neurological damage to progress. If your folate is elevated and you are not supplementing heavily, a concurrent B12 test is advisable.
What Do Low Folate Levels Mean?
Low folate indicates inadequate dietary intake or impaired absorption. Because folate is water-soluble and not stored in fat, levels drop quickly on a poor diet. Causes include insufficient vegetable intake, overcooking food, malabsorption conditions (celiac disease, IBD), excessive alcohol use, certain medications and increased demand during pregnancy. Prolonged deficiency leads to megaloblastic anaemia.
Symptoms to Watch For
- Fatigue and weakness
- Pale skin
- Shortness of breath
- Irritability and mood changes
- Sore, red tongue (glossitis)
- Diarrhoea and digestive issues
- Poor concentration and cognitive difficulties
Who Should Get Tested?
- Women who are pregnant or planning pregnancy
- People who eat few fruits and vegetables
- Those with celiac disease, IBD or other malabsorption conditions
- Heavy alcohol consumers
- Smokers
- People taking medications that affect folate metabolism (e.g. methotrexate, anti-seizure drugs)
How to Prepare for Your Test
Fast for at least 12 hours before this test (water only). Bring valid ID to the lab. If you take a supplement containing biotin (often sold for hair and nails), pause it for two days before the test, as high doses can distort the result.
Order Your Blood Test
Test your Folate levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.
Frequently Asked Questions
What is the difference between folate and folic acid?
Why is folate important during pregnancy?
Is serum folate or red blood cell folate a better test?
Can high folate be harmful?
Reviewed by
Wellth Team
Wellth
Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.
Learn more about our team →Medical Disclaimer
The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.