Folate (Red Blood Cell) measures the amount of folate, a B vitamin (vitamin B9), stored inside red blood cells. Because red blood cells retain folate for the duration of their lifespan (about three to four months), this test reflects longer-term folate status rather than recent dietary intake, which is captured by a serum folate test. This test is used to evaluate the body's folate stores over time. It may be ordered to help assess certain types of anemia, to check for a folate deficiency, or to monitor folate levels in people with conditions affecting nutrient absorption. It is sometimes considered a more stable indicator of folate status than a serum folate measurement.