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Folate, RBC
Test Code467
Alias/See Also
1230100397 | LAB70: RBC Folate
LAB4970: Folate, RBC
LAB70A: RBC Folate | QUEST EAP: 467
LAB4970: Folate, RBC
LAB70A: RBC Folate | QUEST EAP: 467
CPT Codes
82747
Preferred Specimen
2 mL whole blood collected in an EDTA (lavender-top) tube
Minimum Volume
2 mL
Other Acceptable Specimens
Frozen whole blood EDTA submitted in a plastic screw-cap vial
Instructions
Preferred specimen(s)Whole blood collected in an EDTA (lavender-top) tube sent at room temperature will have folate and hematocrit testing performed.
Alternative specimen(s)2 mL frozen (EDTA) whole blood in a transport tube.
Note: HCT testing cannot be performed on a frozen specimen. A default HCT result will be used for calculation of the RBC folate value.
Minimum volume0.2 mL
Collection instructionsBoth 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.
Alternative specimen(s)2 mL frozen (EDTA) whole blood in a transport tube.
Note: HCT testing cannot be performed on a frozen specimen. A default HCT result will be used for calculation of the RBC folate value.
Minimum volume0.2 mL
Collection instructionsBoth 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.
Transport Container
LAVENDER TOP-EDTA
Transport Temperature
EDTA Lavender-top tube: Room temperature
Plastic screw-cap vial: Frozen
Plastic screw-cap vial: Frozen
Specimen Stability
Folate (EDTA)
Room temperature: 5 days
Refrigerated: 5 days
Frozen: 60 days
Hematocrit
Room temperature: 48 hours
Refrigerated: 48 hours
Frozen: Unacceptable
Room temperature: 5 days
Refrigerated: 5 days
Frozen: 60 days
Hematocrit
Room temperature: 48 hours
Refrigerated: 48 hours
Frozen: Unacceptable
Methodology
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
Last Updated: November 4, 2026
