Normal folate levels in children depend on the laboratory and the type of blood test used. MedlinePlus lists a general blood folate range of 2.7–17.0 ng/mL (6.12–38.52 nmol/L), but it also notes that ranges can vary. There is no single number that should be applied to every child; use the reference interval printed on the report and discuss results with the child's clinician.
What blood folate range is commonly used?
Folate, also called vitamin B9, helps the body make DNA, produce genetic material, and support normal cell division. It is important for the production of healthy red blood cells. A folate blood test measures the amount of folate in a blood sample and may be ordered when a healthcare professional suspects a nutritional deficiency or is investigating certain types of anemia.
Different medical laboratories use different reference values. For example, Mayo Clinic Laboratories lists a serum folate level of 4.0 mcg/L or higher as its reference value and considers results below 4.0 mcg/L suggestive of folate deficiency. The units mcg/L and ng/mL have the same numerical value. This is a laboratory-specific interpretation, not a universal pediatric cutoff or a diagnosis on its own.
The National Institutes of Health Office of Dietary Supplements notes that a serum folate concentration above 3 ng/mL generally indicates adequacy. Because clinical sources use somewhat different thresholds, results near these values should be interpreted using the child's laboratory report, medical history, and other relevant findings rather than a number found online.
Do normal folate levels differ by a child's age?
There is no single serum folate reference range that should automatically be used for every child from infancy through adolescence. Laboratory methods and reference intervals can differ, and some laboratories provide age-specific values when appropriate. A clinician should check whether the report uses a pediatric reference interval and ensure that the comparison is suitable for the child's age and the test performed.
It is also important to distinguish a blood folate result from the amount of folate a child needs to consume each day. Daily intake recommendations change as children grow, but they are measured in dietary folate equivalents (DFE), not in the blood concentration reported by a laboratory.
What can a low folate result mean?
A folate level below the laboratory's reference range may be associated with inadequate dietary intake, difficulty absorbing nutrients, or malnutrition. Conditions that affect absorption, including celiac disease, may be relevant in some children. A result alone does not establish the cause, so the clinician may consider the child's usual diet, growth, medical history, medicines, and any digestive symptoms.
When folate deficiency affects red blood cell production, a child may experience tiredness, weakness, difficulty concentrating, irritability, headaches, or shortness of breath. Soreness or ulcers affecting the tongue or inside of the mouth may also occur. These symptoms are not specific to folate deficiency and can have other causes, so persistent or concerning symptoms should be discussed with a healthcare professional. The NIH Office of Dietary Supplements describes these symptoms among the possible effects of folate deficiency.
How do doctors interpret an abnormal folate result?
Healthcare professionals do not rely on the folate number alone. Depending on the circumstances, they may review a complete blood count to assess red blood cells and check vitamin B12 levels. Folate deficiency and vitamin B12 deficiency can produce similar changes in red blood cells, so distinguishing between them may be important before treatment is started. The Merck Manual Professional Edition describes the use of blood counts and folate and vitamin B12 measurements when evaluating suspected deficiency.
The clinician may also consider whether recent changes in diet or supplement use affected the result. Serum folate can change with recent intake, so one measurement may not fully represent longer-term folate status. Red blood cell folate is less affected by short-term dietary changes, although the choice of test depends on the clinical situation and the laboratory's methods.
Can a high folate level be misleading?
A result above the laboratory's reference interval does not automatically mean that a child has a medical problem. Recent folic acid supplements, folate-rich foods, and the conditions under which the blood sample was collected can influence serum measurements. Mayo Clinic Laboratories notes that recent folic acid administration or dietary intake can produce normal or elevated serum results and may mask an underlying deficiency.
Follow the testing laboratory's instructions about fasting and supplements because preparation requirements can differ. Do not stop a prescribed medicine, change a supplement, or start a high-dose folic acid product solely because of a test result. Ask the child's healthcare professional whether the finding requires further evaluation or repeat testing.
How much folate do children need each day?
Daily folate recommendations provide a guide to nutritional intake, not a target blood concentration. The NIH Office of Dietary Supplements lists the following recommended daily amounts for children and adolescents:
| Age group | Recommended daily folate intake |
|---|---|
| Birth to 6 months | 65 mcg DFE |
| 7–12 months | 80 mcg DFE |
| 1–3 years | 150 mcg DFE |
| 4–8 years | 200 mcg DFE |
| 9–13 years | 300 mcg DFE |
| 14–18 years | 400 mcg DFE |
Folate is naturally present in foods such as leafy green vegetables, beans, peas, citrus fruits, and some other vegetables. Folic acid, a form of vitamin B9, is also added to certain fortified grain products and breakfast cereals. A varied diet can help children meet their nutritional needs, but a child's individual dietary requirements may differ depending on their health and circumstances.
These intake recommendations should not be used to calculate or predict a child's blood folate level. If a test result is outside the reported reference range, the appropriate next step is to discuss it with the child's healthcare professional, who can determine whether dietary changes, additional testing, or treatment is needed.