Sign in →

Test Code Billings Clinic: 4195 Vitamin B12 and Folate, Serum

Important Note

This test should not be requested on patients who have recently received methotrexate or other folic acid antagonist. For patients receiving methotrexate and leucovorin therapy, folate results should be interpreted with caution.

 

Do not test samples from patients who take high doses of biotin.

Performing Laboratory

Billings Clinic Laboratory: Chemistry

Useful For

  • Investigation of suspected folate deficiency
  • Investigation of macrocytic anemia
  • Workup of deficiencies seen in megaloblastic anemias

Methodology

Direct Chemiluminescence

 

Specimen Requirements

Serum should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.

 

Serum

  • Draw blood in a plain, red-top tube(s) or a serum gel tube(s).
  • Spin down and send 1.0 mL of serum frozen

Storage/Stability

Specimen Type Temperature Time
Serum Refrigerated 2 days
  Frozen (preferred) 1 month
  Ambient 8 hours

 

Reject Due To

  • Hemolysis
  • Specimens with apparent contamination
  • Samples frozen/thawed more than once
  • Samples containing fluoride
  • Samples containing ascorbic acid
  • Methotrexate and Leucovorin (folinic acid) interfere with the measurement of folate

Reference Values

Folate: 3.1 - 17.5 ng/mL

Vitamin B12: 193 - 986 pg/mL

Day(s) Test Set Up

Daily

Test Classification and CPT Coding

82607 - vitamin B12

82746 - folate

LOINC Code Information

Reporting Name LOINC Code
Folate 2284-8
Vitamin  B12 2132-9

 

Profile/Testing Information

  • This test should not be requested on patients who have recently received methotrexate or other folic acid antagonist.
  • Clinical vitamin B12 deficiency can occur in patients with B12 levels in the normal range. Serum methylmalonic acid levels may be helpful.