Folate (Folic Acid): Reference Range, Interpretation, …

There are notable differences between results obtained for red cell and serum folate assays between manufacturers, which is not an uncommon occurrence for any unstandardized assay on the market. Bias between test methods and platforms may be as low as 10% and as high as 70%, despite similar claims of traceability, and occurs throughout the analytical range of the assays. Therefore, there is currently no one standard for folate measurement and values can vary significantly from one laboratory to the next because of method differences.

Obesity Is Associated with Increased Red Blood Cell Folate …

is essential for DNA synthesis, which is required for normal red blood cell ..

11 Red Blood Cell Disorders | Anemia | Folic Acid

There are a number of methods which can be utilized to quantitate serum or red cell folate. These include microbiologic assays, competitive protein-binding assays, or chromatography. A majority of laboratories, including Mayo, use a protein-binding assay with chemiluminescent detection for both serum and red blood cell folate, where the red cell hemolysate is prepared by lysing with ascorbic acid, which releases the intracellular folate, again primarily in the 5-tetrahydrofolate form.

Formation of Red Blood Cells (Erythrocytes) Folate ..

Analytical imprecision is notably worse with red cell folate assays compared to serum folate assays. This has been well documented in the literature and noticeable in proficiency testing surveys, where the variability even within the same peer group may be up to 50%. Manual sample preparation and variability among procedures to completely lyse the red blood cells are likely responsible for much of this variation.

Serum and red blood cell folate values obtained ..

We further undertook a 10-year retrospective analysis of red blood cell and serum folate results to examine ordering patterns and evaluate the clinical utility of RBC folate in our patient population. Results were retrieved from all serum and RBC folate tests from the laboratory information system at Mayo ordered on inpatients and outpatients between 1999-2009. Data for patients who had simultaneous orders for serum and red cell folate were analyzed and chart reviews were conducted on those patients with normal serum folate but low RBC folate; these are the individuals who have the potential for misdiagnosis if screened with a serum folate alone. Abnormal values were defined two-fold: first by our current reference ranges (

serum and red blood cell folate ..

Folate deficiency manifests clinically in a variety of ways; notably it is strongly linked to an increased risk of neural tube defects and several observational and controlled trials have demonstrated that neural tube defects are significantly reduced with periconceptual folic acid supplementation. Individuals with folate deficiency may present clinically with unexplained, nonspecific neurological symptoms including dementia, weakness, and headaches. Folate and vitamin B12 deficiencies are both associated with a reduction in hemoglobin and megaloblastic changes in the bone marrow or other tissues. Megaloblastic anemia is the primary manifestation of folate deficiency, where erythrocytes become abnormally large and nucleated due to the lack of folate necessary for DNA synthesis and cell division.

The amount of folate inside the red blood cell ..

True folate deficiency in the current era of FDA-mandated folic acid supplementation is exceedingly rare. There is no evidence to support routine ordering of RBC or serum folate, but serum folate concentrations provide equivalent clinical information to RBC folate in the assessment and diagnosis of folate deficiency. Based on these statistics, and because serum folate provides equivocal results to RBC folate in almost all clinical scenarios, routine ordering of RBC folate is no longer warranted. Furthermore, investigation of megaloblastic anemia should preferentially be initiated with vitamin B12 testing instead of folate due to the low incidence of modern folate deficiency. In the absence of B12 deficiency, it is more cost effective to simply supplement with folic acid rather than routinely test and monitor a patient's folate status, similar to other nutritional deficiencies such as vitamin D.