Serum Folate (Vitamin B9) (Folate)
Serum folate measures circulating 5-methyltetrahydrofolate (5-MTHF), the primary coenzyme for de novo purine/thymidylate synthesis and homocysteine remethylation.
Standard vs. Optimal Reference Rangesng/mL
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
> 4.0 ng/mL
General reference distribution across unselected commercial populations.
10.0 - 20.0 ng/mL (RBC Folate > 400 ng/mL)
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Dietary polyglutamates are hydrolyzed to monoglutamates in jejunal brush borders and converted to active 5-MTHF by dihydrofolate reductase and MTHFR. Transfers one-carbon units for DNA synthesis and repair.
Differential Diagnosis
Elevated Levels (Folate High)
- •Recent high dietary intake or multivitamin supplementation
Low Levels (Folate Low)
- •Inadequate leafy green vegetable intake / Alcoholism
- •Malabsorption (Celiac disease)
- •Antifolate medication use (Methotrexate, Trimethoprim)
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Standard 10 to 12 hour overnight fast is recommended; avoid high-dose vitamin and mineral supplements for 24 hours prior to blood draw. Protect light-sensitive specimens (such as Vitamin B6, B12, and Folate) from ultraviolet light exposure by using amber collection tubes. Centrifuge and separate serum or plasma promptly to prevent in vitro leakage of intracellular minerals (e.g. magnesium, potassium) from red blood cells.
Reflexive Testing Protocol:
- Functional metabolic surrogate markers (Methylmalonic Acid for B12, Homocysteine for B6/B12/Folate, Red Blood Cell Magnesium)
- Complete Metabolic Panel and Ionized Calcium to evaluate electrolyte and mineral balance
- Celiac disease serology (Tissue Transglutaminase IgA with Total IgA) to screen for occult enteropathic malabsorption
- Parathyroid Hormone (PTH) and 24-Hour Urine Calcium quantification in cases of abnormal Vitamin D or calcium homeostasis
- Comprehensive Nutritional & Heavy Metal Trace Element panel via ICP-MS if multiple deficiencies are present
Clinical Citations & Primary Literature (1)
- [1]Folate Metabolism in Human Health and Disease - Nature Reviews Endocrinology (2021). PMID: 33792055
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Folate (Vitamin B9) (Folate) into overall healthspan optimization.