Folate, RBC

Test Code

Quest Code

CPT Codes

Preferred Specimen
2 mL whole blood collected in an EDTA (lavender-top) tube

Minimum Volume
0.2 mL

Other Acceptable Specimens
Whole blood EDTA submitted in a plastic screw-cap vial, frozen

Whole blood EDTA (lavender-top) tube sent at room temperature will have folate and hematocrit testing performed. Wrap tube in aluminum foil to protect from light. Both the HCT and folate will be performed on this tube.

If sample is sent frozen, a default hematocrit will be used for calculation of the RBC folate. Do not freeze as this will affect the HCT.

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.

Transport Temperature
Lavender-top tube: Room temperature
Plastic screw-cap vial: Frozen

Specimen Stability
Folate (EDTA)
Room temperature: 5 days
Refrigerated: 5 days
Frozen: 60 days

Room temperature: 48 hours
Refrigerated: 48 hours
Frozen: Unacceptable

Immunoassay (IA)

Setup Schedule
Set up: Mon-Fri; Report available: Next day

Reference Range
>280 ng/mL RBC

Clinical Significance
Folate levels have diagnostic significance in nutritional deficiencies, especially in cases of severe alcoholism, function damage to the upper third of small bowel, pregnancy and various forms of megoblastic anemia. Since serum folate levels are subject to rapid changes reflecting diet and absorption, RBC folate may be a better diagnostic tool since the levels remain fairly constant.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.