Folate, RBC and Serum

CPT: 82746; 82747; 85014
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  • Folates, RBC and Serum (With Hct)

Test Includes

RBC folate; serum folate; hematocrit

Special Instructions

This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.

Expected Turnaround Time

1 - 2 days

Specimen Requirements


Whole blood (two tubes) and serum


Two full lavender-top (EDTA) tubes and one red-top tube or gel-barrier tube


Transfer 7 mL from one whole blood tube into a plastic transport tube and freeze. Refrigerate second whole blood tube. If a red-top tube is used, transfer separated serum to a plastic transport tube. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions

Freeze whole blood transport tube and refrigerate all other specimens.

Patient Preparation

Verify that the patient has not had vitamins containing folic acid during the previous three to five days; if so, consult the physician.

Causes for Rejection

No frozen whole blood; no refrigerated whole blood; plasma specimen; hemolysis; transport tubes with whole blood for the hematocrit portion

Test Details


Detect folate deficiency; monitor therapy with folate; evaluate megaloblastic and macrocytic anemia


Folates: Electrochemiluminescence immunoassay (ECLIA); Hematocrit: Automated cell counter

Reference Interval

RBC folate: 499−1504 ng/mL; serum folate: >3.0 ng/mL


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
285700 Folate, RBC and Serum 266019 Folate, Hemolysate ng/mL 2282-2
285700 Folate, RBC and Serum 005058 Hematocrit % 4544-3
285700 Folate, RBC and Serum 266022 Folate, RBC ng/mL 2283-0
285700 Folate, RBC and Serum 002020 Folate (Folic Acid), Serum ng/mL 2284-8

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