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Biomarkers · Chemical

Folate (Folic Acid), Serum

A vitamin B test measures the amount of one or more B vitamins in your blood or urine (pee). B vitamins are nutrients that your body needs to work well and stay healthy.

Vitamin B Test, MedlinePlus, National Library of Medicine

Folate, also called vitamin B9, is a B vitamin that the body uses to make healthy new cells. Serum folate reflects the body's folate status, and guidelines treat it as the first test to assess that status.

Primary unit
ng/mL
LOINC codes
2284-8
Tests that measure Folate (Folic Acid), Serum
Labcorp 7, Quest Diagnostics 6

See why clinicians order the test

  • Clinicians often order folate together with vitamin B12 when symptoms point to certain types of anemia.

    Goal: Anemia

  • Clinicians order B vitamin testing, which can include folate, when symptoms suggest a person may not be getting enough B vitamins.

    Goal: Vitamin B12 and folate

  • Clinicians may order B vitamin testing even without symptoms when a condition or habits raise the risk of a vitamin B deficiency.

Read with companion markers

  • Vitamin B12

    Labs often measure folate and vitamin B12 together in a single vitamin B12 and folate test.

Check what can shift results

  • Condition

    • Inflammation in the body can affect vitamin B test results, which makes their meaning less clear.

  • Medicine

    • Certain medicines can affect vitamin B test results, so the meaning of a result is not always clear.

Prepare for the test

  • The test may require fasting, with no eating or drinking, for several hours before a vitamin B blood test.

Each statement links to the source we wrote it from. Last updated October 19, 2026.

Ranges

Compare the reference ranges labs publish with guideline targets, diagnostic cut-offs, study-based ranges and practitioner targets. Move across the rows to check a value against each range, and open a source from the legend. How to read these ranges

Folate (Folic Acid), Serum, ng/mL

Labs
Cut-offs
  • Lab reference ranges2 labs
  • Diagnostic cut-offs1 cut-off
All 3 published ranges, with sources

Lab reference ranges

Diagnostic cut-offs

Tests

Check the catalog code, specimen, method and preparation for every test that measures Folate (Folic Acid), Serum. Select up to five tests to compare them side by side.

Labcorp 7 tests

Single-analyte tests

  • Folate (Folic Acid) 002014

    Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Electrochemiluminescence immunoassay (ECLIA)
    Collection
    If a red-top tube is used, transfer separated to a plastic transport tube.
    Reference notes
    >3.0 ng/mL
    Labcorp catalog page

Panels that include this biomarker

  • Vitamin B12 and Folates 000810

    2 analytes · Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Electrochemiluminescence immunoassay (ECLIA)
    Collection
    If red-top tube is used, transfer separated serum immediately to a plastic transport tube.
    Labcorp catalog page

  • Pre-Bariatric Surgery Micronutrient Profile 259104

    9 analytes · Serum · Fasting not stated · Turnaround 2 - 4 days

    Method and collection
    Method
    See individual test components.
    Labcorp catalog page

  • Anemia Profile B 042077

    26 analytes · Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    See individual tests.
    Labcorp catalog page

  • Post-Bariatric Surgery Micronutrient Profile 259129

    33 analytes · Serum · Fasting not stated · Turnaround 3 - 5 days

    Method and collection
    Method
    See individual test components.
    Labcorp catalog page

  • Post-Bariatric Surgery Comprehensive Profile 259090

    50 analytes · Serum · Fasting not stated · Turnaround 5 - 7 days

    Method and collection
    Method
    See individual test components.
    Labcorp catalog page

Quest Diagnostics 6 tests

Single-analyte tests

  • Folate, Serum 466

    Serum · Fasting not stated · Turnaround Set up: Mon-Fri; Report available: 5 days

    Method and collection
    Method
    Immunoassay (IA)
    Collection
    Dietary supplements containing biotin may interfere in assays and may skew analyte results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation. Note: If transport to performing laboratory will exceed 24 hours please transport refrigerated (cold packs)
    Reference notes
    ≤4 years Not established 5-9 years >7.1 ng/mL 10-17 years >8.0 ng/mL ≥18 years Low <3.4 ng/mL Borderline 3.4-5.4 ng/mL Normal >5.4 ng/mL
    Quest Diagnostics catalog page

  • Micronutrient, Folate 10188

    Serum · Fasting not stated · Turnaround Set up: Tues-Sat

    Method and collection
    Method
    Immunoassay (IA)
    Collection
    Patients should be 18 years of age or older. Dietary supplements containing biotin may interfere in assays and may skew analyte results to be either falsely high or falsely low. For patients receiving the recommeded daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation. Note: If transport to performing laboratory will exceed 24 hours please transport refrigerated (cold packs).
    Reference notes
    ≥18 years >5.4 ng/mL Reference range not available for individuals <18 years for this micronutrient test.
    Quest Diagnostics catalog page

Panels that include this biomarker

  • Vitamin B12 (Cobalamin) and Folate Panel, Serum 7065

    2 analytes · Serum · Fasting not stated

    Method and collection
    Method
    Immunoassay (IA)
    Collection
    Dietary supplements containing biotin may interfere in assays and may skew analyte results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation. Note: If transport to performing laboratory will exceed 24 hours please transport refrigerated (cold packs)
    Reference notes
    See individual tests
    Quest Diagnostics catalog page

  • Dementia Panel, Secondary Causes 34541

    3 analytes · Serum · Fasting not stated

    Method and collection
    Method
    See individual tests
    Preparation
    Fasting specimen is preferred. Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks. According to the assay manufacturer Siemens: "Samples containing fluorescein can produce falsely depressed values when tested with the Advia Centaur TSH3 Ultra assay."
    Collection
    EDTA (lavender-top): Maintain specimen at room temperature. Do not refrigerate. If multiple draw, collect EDTA (lavender-top) tube last. Traumatic draw can introduce thromboplastin and trap WBC and platelets. Refrigeration can precipitate fibrin and trap WBC and platelets. Serum note: If transport to performing laboratory will exceed 24 hours please transport refrigerated (cold packs).
    Reference notes
    See Laboratory Report
    Quest Diagnostics catalog page

  • Micronutrients, B-Vitamin Panel 10195

    7 analytes · Serum · Fasting required

    Method and collection
    Method
    Immunoassay (IA) • Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)
    Preparation
    Overnight fasting is required. Avoid vitamin supplements for 24 hours prior to collection.
    Collection
    Patients should be 18 years of age or greater. Folate & Vitamin B12: Transfer 2 mL (1 mL min) serum into plastic transport tube, ship frozen. Vitamin B2, B3, B5: Transfer 2 mL (1 mL min) serum into an amber vial (or wrap with aluminum foil), ship frozen. Vitamin B6: Transfer 3 mL (1 mL min) EDTA plasma into an amber vial (or wrap with aluminum foil), ship frozen. ⁠⁠⁠⁠⁠⁠⁠Separate cells within 24 hours by centrifugation for 5-10 minutes. Transfer plasma to an amber polypropylene or polyethylene transport tube to protect from light. Alternately, neutral color polypropylene or polyethylene tube can be used if wrapped in aluminum foil. Freeze the tubes at -10 to -30° C. Ship frozen. Vitamin B1: Transfer 3 mL (1 mL min) EDTA whole blood into an amber vial (or wrap with aluminum foil), ship frozen. Dietary supplements containing biotin may interfere in assays and may skew analyte results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation. Remove serum or plasma from cells within 4 hours of collection.
    Reference notes
    ≥18 years Folate | >5.4 ng/mL Vitamin B1 (Thiamine) | 78-185 nmol/L Vitamin B2 | 6.2-39.0 nmol/L Vitamin B3 | ≤110 ng/mL Vitamin B5 | <275 ng/mL Vitamin B6 | 5.1-54.8 ng/mL Vitamin B12 | 200-1100 ng/mL Reference range not available for individuals <18 years for this micronutrient test.
    Quest Diagnostics catalog page

  • Cognitive Assessment Panel with Reflex to T4 Free 18634

    8 analytes · Serum · Fasting not stated

    Method and collection
    Method
    Spectrophotometry (SP) • Immunoturbidimetric • Enzymatic • Mass Spectrometry (MS) • Electronic Cell Sizing/Counting/Cytometry/Microscopy • Immunoassay (IA)
    Preparation
    Fasting is preferred Additional Considerations for Patient Preparation: Comprehensive Metabolic Panel: Administration of STRENSIQ may interfere in certain assays and may falsely elevate values. For patients receiving STRENSIQ, consideration should be given to using alternate methods. TSH: Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks after angiography. According to the assay manufacturer Siemens: samples containing fluorescein can produce falsely depressed values. Folate: Dietary supplements containing biotin may interfere in assays and may skew analyte results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation.
    Collection
    Serum for Homocysteine: Red-top tubes: Place the specimen in a refrigerator or ice bath for 30 minutes after collection. Centrifuge the specimen as soon as possible after complete clot formation has taken place. Transfer the serum to a plastic screw-capped vial. Barrier gel separator tubes: Place the specimen in a refrigerator for 30 minutes after collection. Centrifuge the specimen as soon as possible after complete clot formation has taken place. Do not place barrier tubes in an ice bath as freezing may prevent the barrier gel from adequately separating serum from cells. Serum for other tests, 3 SSTs: Collect using standard venipuncture techniques. Separate from clot as soon as possible after visible clot formation, usually 30 minutes after collection. Whole blood, 1 EDTA: Maintain specimen at room temperature. Do not refrigerate. If multiple draw, collect lavender-top tube last. Traumatic venipuncture tap can introduce thromboplastin and trap white blood cells and platelets. Refrigeration can precipitate fibrin and trap white blood cells and platelets.
    Reference notes
    See Laboratory Report
    Quest Diagnostics catalog page

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Goals and conditions

We link Folate (Folic Acid), Serum to these goals and conditions from named guidelines and studies.

Sources

Check the guidelines, studies and lab catalogs behind every range and link on this page. Open a source to see each claim it backs.

Clinical guidelines

Lab catalogs

Reference sources

Codes and registries

Verify these ranges and sources

We compile this page from named laboratory catalogs, guidelines and studies. Labs calculate reference intervals from the people they test, for one assay method and one population group, so an interval describes that population rather than an optimal target.

Interpret your own results with a licensed clinician, or track your lab history and health goals in Aumnivida.

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