Vitamin B12 and Folate
Test ID: A896
Vitamin B12 and folate are B vitamins. They play important roles in health and wellness, particularly cell metabolism and synthesis of red blood cells. The best sources of B vitamins are meat, eggs, and dairy products, as well as leafy green vegetables and legumes for many B vitamins (with the notable exception of vitamin B12, which is generally not present in plant foods).
Vitamin B deficiency is most often caused by malabsorption from food, pernicious anemia, or dietary deficiency. Deficiency is characterized by megaloblastic anemia, which causes weakness, fatigue, difficulty concentrating, irritability, headaches, heart palpitations, and shortness of breath.
How to order a test
What is Included?
Measurement of blood vitamin B12 and folate levels by chemiluminescent microparticle Intrinsic Factor assay (B12) and chemiluminescent microparticle immunoassay (folate).
1 – 3 business days
The turnaround time is not guaranteed. The average turnaround time is 1 – 3 business days from the date that the sample arrives at the laboratory. Shipping time for the sample is not included. Additional time is required if the case requires confirmatory or reflex testing, or if the sample is insufficient, or if a recollection is required.
Additional Information and Resources
Preparation Before Specimen Collection
Collect blood sample for this test after fasting overnight (for 8 – 12 hours). Fasting means that no food or drink (aside from water) is to be consumed.
Ensure blood sample is not exposed to bright light.
50 μL in a microtainer
Microtainer (regular blood tube)
This test requires a blood sample from a finger prick. All supplies for sample collection are provided in the kit.
- First wash and dry hands. Warm hands aid in blood collection.
- Clean the finger prick site with the alcohol swab and allow to air dry.
- Use the provided lancet to puncture the skin in one quick, continuous and deliberate stroke.
- Wipe away the first drop of blood.
- Massage hand and finger to increase blood flow to the puncture site. Angle arm and hand downwards to facilitate blood collection on the fingertip.
- Drip blood into the microtainer tube.
- Dispose of all sharps safely and return sample to the laboratory in the provided prepaid return shipping envelope.
NOTES: Avoid squeezing or ‘milking’ the finger excessively. If more blood is required and blood flow stops, perform a second skin puncture on another finger. Do not touch the fingertip.
Maintain specimen at temperatures between 2°C and 30°C during storage and transport.
Blood samples can be refrigerated or kept at room temperature for up to 7 days.
Causes for Rejection
- Incorrect or incomplete patient identification
- Incorrect specimen collection
- Inappropriate storage and transport conditions
- Incorrect specimen volume
To measure vitamin B12 and folate levels in a blood sample for the detection of deficiency and to evaluate megaloblastic and macrocytic anemia.
- This report is not intended for use in medico-legal applications.
- These results should be interpreted in conjunction with other laboratory and clinical information.
- Correct specimen collection and handling is required for optimal assay performance.
- False results may occur in specimens from individuals that have received preparations of mouse monoclonal antibodies for diagnosis or therapy. Additional clinical or diagnostic information may be required for these specimens.
- Assay interference may occur in specimens from individuals routinely exposed to animals or to animal serum products. Additional clinical or diagnostic information may be required for these specimens.
- Hemolysis exhibits negative interference in this vitamin B12 assay
- Specimens from individuals with renal impairment or failure may result in falsely depressed folate values.
- Some chemotherapeutic agents, including methotrexate, aminopterin, and folinic acid, cross react with folate binding protein in this assay.
Chemiluminescent microparticle Intrinsic Factor assay (Alinity i B12 assay)
Chemiluminescent microparticle immunoassay (Alinity i Folate assay)
Vitamin B12: 200 – 835 pg/mL
This reference range was obtained from Reed R. (2020). Clinical Chemistry Learning Guide Series. Editors Armbruster D & Cooper K. Abbott.
Levels above 300 or 400 pg/mL are rarely associated with B12 deficiency induced hematological or neurological disease, respectively. Further testing is suggested for symptomatic patients with B12 levels between 100 and 300 pg/mL (hematological abnormalities), and between 100 and 400 pg/mL (neurological abnormalities).
Folate: 3.1 – 20.5 ng/mL
This reference range was obtained from the Alinity i Folate package insert.
Folate deficiency is typically associated with serum levels less than 3.5 ng/mL.