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Folate (Vitamin B9) in Serum or Plasma

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of folate (vitamin B9), an essential nutrient important for red blood cell production and DNA synthesis. Low levels may indicate poor nutrition or certain health conditions.

Quick summary

["Folate helps prevent birth defects and supports overall cell growth; low levels may need dietary or medical attention."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
61546-8
Short code
Years folic acid folate PhenX
Synonyms
Years folic acid folate PhenX
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
2.7
Ref high
17
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
phenx
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms like fatigue, weakness, or pale skin, or if you have conditions like anemia, pregnancy, or alcohol use. It can also help diagnose deficiencies or monitor treatment for conditions like Crohn’s disease or certain cancers.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if your blood is drawn early in the morning. Wear comfortable clothing and arrive with an ID for your healthcare provider.

How the Test Is Performed

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a quick pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are compared to a reference range, but exact values can vary by lab. Low levels may signal a deficiency, while high levels could indicate liver disease or certain medications. Your provider will discuss your specific results with you.

Reference range

NCBI: Folate 2.7-17.0 ng/mLN/A

Specimen: serum

Fasting for 8-12 hours preferred for some tests. Inform about supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Folate Level

Frequently asked questions

What causes low folate levels?
Low folate can result from poor diet (low intake of leafy greens, fortified foods), alcohol use, certain medications, or conditions like Crohn’s disease or malabsorption.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab. Your provider will contact you once they have the results.
Can folate levels be raised with supplements?
Yes, folate supplements or fortified foods can help raise levels, but your provider may recommend testing again to monitor changes.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy