RBC Folate
Folate stored inside red blood cells, reflecting folate status over the previous 2-3 months.
| Typical reference range | above 280 ng/mL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Folate is incorporated into red cells as they are made and stays there for their lifespan, so RBC folate reflects longer-term folate availability than serum folate.
Why it matters
RBC folate is less affected by recent meals and better reflects tissue stores. Levels above about 400 ng/mL (906 nmol/L) are associated with the greatest reduction in neural tube defect risk.
What a high result can mean
High levels reflect sustained supplementation or fortified food intake.
What a low result can mean
Low levels indicate chronic folate deficiency; they can also be falsely low in B12 deficiency because B12 is needed to retain folate in cells.
What affects the result
Results vary by method; some labs calculate it from whole-blood folate and hematocrit. Interpret with serum folate, B12 and MCV.
Units and conversion
Usually reported in ng/mL.
- From nmol/L: multiply by 0.441 to get ng/mL
Also called on lab reports
Folate, RBC, Red Blood Cell Folate, Folate, Red Blood Cell, Folate, RBC (Calc), Erythrocyte Folate
Related tests: Vitamins & Nutrients
This page is educational and does not replace advice from a healthcare professional.