Folate, or vitamin B9, is a generic term for a water-soluble vitamin obtained from the diet that is involved in the transfer of methyl groups (i.e., single carbon-containing groups) in multiple biochemical metabolic pathways, including nucleic acid biosynthesis and methionine/homocysteine metabolism. Folate metabolism is closely linked to vitamin B12, cobalamin. Folate deficiency can be implicated in many disease states and processes; however, it is usually easily remedied with either a change in diet or a dietary supplement of the synthetic form, folic acid (Schrier, 2018a; Supplements, 2018).
Folate, or vitamin B9, naturally occurs as polyglutamated compounds (pteroylpolyglutamates) in many plant and animal products. The synthetic form is a monoglutamate-containing compound called folic acid. Folic acid is more chemically stable for commercial production and storage, but it is less bioavailable than the naturally occurring folate (Schrier, 2018a). Folate biochemically is a coenzyme in single-carbon transfers in vivo and is directly linked to the cobalamin (vitamin B12) cycle, methionine metabolism, and nucleic acid biosynthesis. Dietary folates are hydrolyzed via γ-glutamylhydrolase (or folate conjugase) prior to absorption in the intestinal mucosa (Medicine, 1998). Both folate and vitamin B12 are required for formation of 5,10-methylene tetrahydrofolate, which is the cofactor involved in purine synthesis. Methylenetetrahydrofolate reductase (MTHFR) is the enzyme responsible in converting 5,10-methylene tetrahydrofolate to 5-methyl tetrahydrofolate, which is required for methionine synthase, the enzyme that converts homocysteine to methionine.
Role of Folate in Anemia
Macrocytic anemia refers to anemias that have high mean corpuscular volume with large RBCs. Megaloblastic anemia is a specific macrocytic anemia due to nucleic acid metabolic defects that result in "nuclear-cytoplasmic dyssynchrony, reduced number of cell divisions in the bone marrow, and nuclear abnormalities in both myeloid and erythroid precursors" caused by folate and/or vitamin B12 deficiency (Schrier, 2018b). These abnormal RBCs are the principle clinical manifestations of folate deficiency and symptoms "include weakness, fatigue, difficulty concentrating, irritability, headache, heart palpitations, and shortness of breath" (Supplements, 2018).
Folate and Neural Tube Defects (NTDs)
NTDs develop early in pregnancy and are malformations of the brain and/or spine that include spina bifida and anencephaly. Folate deficiency is directly linked to NTDs. The role of folate in NTD development is not well-characterized. The role of folate in either the methylation cycle or nucleic acid synthesis has been suggested to play a part in NTD development during embryogenesis, and some studies have indicated that it is the bioavailability of specific folates in women that can increase the likelihood of NTDs (Imbard, Benoist, & Blom, 2013; Rothenberg et al., 2004). Women typically do not obtain enough folate from diet alone, so women of childbearing age are recommended to take a synthetic folic acid supplement to decrease the likelihood of NTDs in offspring (Bibbins-Domingo et al., 2017). To decrease the occurrence of NTDs and folate deficiency, the United States and Canada mandated folic acid supplementation to cereal grains in 1998, and as of March 2018, "87 countries have legislation to mandate fortification of at least one industrially milled cereal grain" (Initiative, 2018). A review by Imbard et al. (2013) of 17 different studies of the impact of folic acid fortification on NTD rates shows that 16 show a decrease in the rate of NTDs. Only a study of the rate of NTDs in California showed no decline since fortification. The reduction of the United States overall was 26-30% since folic acid fortification (Imbard et al., 2013).
Causes of Folate Deficiency
Folate deficiency can be caused by dietary intake. Nutritional deficits can occur due to diet, alcoholism, depression, and even overcooked foods. Many malabsorptive disorders, such as celiac disease and ulcerative colitis, can also result in a decrease in folate uptake. Bariatric procedures can result in decreased absorption, as well. Drugs, including methotrexate and trimethoprim, can also cause a folate deficiency. An increased need of folate during pregnancy and lactation cause folic acid deficiency (Schrier, 2018b).
Methodology of Folate Testing
Folate concentrations have been measured from serum, erythrocytes (RBC), and urine. Serum folate levels may not "differentiate between what may be a transitory reduction in folate intake or chronic folate deficiency accompanied by depleted folate stores and functional changes" (Medicine, 1998). RBCs have a lifespan of approximately 120 days, and folate is only taken in during initial erythropoiesis; consequently, RBC folate concentrations are less likely to be affected by transitory dietary fluctuations. However, Wu et al. (1975) show that both RBC folate and serum folate levels correlate to hepatocyte folate levels (Medicine, 1998; Wu, Chanarin, Slavin, & Levi, 1975). Galloway and Rushworth (2003) released a study in conjunction with the National Pathology Alliance review in the United Kingdom comparing data of laboratories of the National Health Service that routinely use serum folate testing only, RBC folate testing only, or both serum and RBC folate testing together. They conclude that there is no need to use both tests to determine folate concentration as an initial screen. "The serum folate assay provided equivalent information to the measurement of red cell folate and evidence from the literatures [sic] suggest that the serum folate assay should be the method of choice" (Galloway & Rushworth, 2003).
A 2010 study by Shojania and von Kuster investigated the use of serum folate testing (SF) and RBC folate testing (RF) in cases of anemia in a country that has mandated folic acid supplementation in grain products. By examining the data for folate testing in anemia at two different teaching hospitals in Canada, they report that in one hospital in 2001 "11 out of 2,154 (0.5%) SF were low (<7.0 nmol/L) and 4 out of 560 (0.7%) RF were low (<417 nmol/L). In no subject with low SF or RF could the anemia be attributed to folate deficiency." For the other hospital, the data from 1999-2001 show that "19 out of 991 (1.9%) had low RF (<225 nmol/L) but in only 2 patients (0.2%) the low RF was in folate deficiency anemia range" (Shojania & von Kuster, 2010). The authors conclude that neither serum folate testing nor RBC folate testing is justified in cases of anemia for folic acid fortified countries due to such low incidence rates of folate deficiency anemia.
Another study by Joelson et al. (2007) examined the records of three different hospitals in the U.S. that service a high number of indigent patients. They reported the data from three non-consecutive years (1997, 2000, and 2004) to examine the impact of folate fortification in food products. Using the RBC folate levels only with an RBC folate cutoff value of 160 ng/mL (363.6 nmol/L), they show that "the combined incidence of folate deficiency decreased from 4.8% in 1997 to 0.6% in 2004. … Even when the folate concentration was found to be low, the majority of these subjects did not have macrocytosis." Their study included a total of 4,134 RBC folate tests performed over the course of the three years examined. It is of interest to note that the number of tests performed increased from 813 in 1997 to 1,759 in 2004. The authors do note a potential limitation of the study, since they cannot separate the data of the patients into specific groups (pregnant women, alcoholics, socioeconomic classes, and so on). The authors conclude "that folate deficiency has become a rare event in the United States, and the utility of routine folate measurements for patients with anemia and/or increased mean corpuscular volume are difficult to justify" (Joelson, Fiebig, & Wu, 2007).
Urinary folate levels do not reflect either the stored folate concentrations or the fluctuations in folate concentration due to transitory dietary changes. Only about 1-2% of the folate excreted in the urine is unmetabolized and "excretion continued in the face of advanced folate depletion" (Medicine, 1998). One study of ten postmenopausal women on a low folate diet measured folate turnover using urinary testing of folate and folate metabolites. "Folate intake did not significantly influence ApABG (para-acetamidobenzoylglutamate) or pABG (para-aminobenzoylglutamate) excretion." ApABG and pABG, along with pterins, are the major folate catabolites. The authors conclude that "the rate of folate catabolite excretion is related mainly to masses of slow-turnover folate pools governed by long-term folate intake" (Gregory, Swendseid, & Jacob, 2000).
The FDA has approved multiple tests for the evaluation of both human serum folate and red blood cell folate levels, either alone, together, or included in panels. As of 6/1/2018, there are 82 records on the FDA Devices database for folate.
- Measurement of serum folate concentration is considered MEDICALLY NECESSARY for evaluation of patients when all of the following criteria are met:
- patient was diagnosed with megaloblastic, macrocytic anemia due to folate deficiency; AND
- megaloblastic anemia and/or macrocytosis does not resolve after folic acid treatment
- Measurement of serum folate concentration is considered NOT MEDICALLY NECESSARY for any other indications not described above
- Measurement of RBC folate is considered NOT MEDICALLY NECESSARY for any indications
1991/1992 Centers for Disease Control and Prevention (CDC) Morbidity and Mortality Weekly Report (MMWR) (Marshall, Williams, & Williams, 1991; Prevention, 1992)
Both in 1991 and 1992, the CDC addressed the need for women to consume folic acid daily. In the first recommendation, the CDC recommended that women who had already had at least one pregnancy with a neural tube defect (NTD) consume 4 mg of folic acid per day. “Women should take the supplement from at least 4 weeks before conception through the first 3 months of pregnancy.” This recommendation required a physician’s supervision and “was not intended for 1) women who have never given birth to an infant or had a fetus with a neural tube defect, 2) relatives of women who have had an infant or fetus with a neural tube defect, 3) women who themselves have spina bifida, or 4) women who take the anticonvulsant valproic acid—a known cause of spina bifida.” In 1992, the CDC modified the recommendation to include all women of childbearing age to consume folate, since the addition of folate would potentially decrease the number of NTDs by 50%. “All women of childbearing age in the United States who are capable of becoming pregnant should consume 0.4 mg of folic acid per day for the purpose of reducing their risk of having a pregnancy affected with spina bifida or other NTDs. Because the effects of high intakes are not well known, but include complicating the diagnosis of vitamin [B12] deficiency, care should be taken to keep total folate consumption at less than 1 mg per day, except under the supervision of a physician. Women who have had a prior NTD-affected pregnancy are at high risk of having a subsequent affected pregnancy. When these women are planning to become pregnant, they should consult their physicians for advice.” Neither recommendation from the CDC included a requirement for either serum folate or red blood cell folate concentration.
1998 Institute of Medicine (IOM) (Medicine, 1998)
The Institute of Medicine released its detailed report titled Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline in 1998. This report does not outline any recommendation concerning determining the concentration of either serum folate or red blood cell folate concentrations; however, the table below outlines its recommendations concerning the upper limits (UL) of daily intake of folate for various groups (taken from (Medicine, 1998)):
|ULs for Infants
||Not possible to establish for supplemental folate
|ULs for Children
||300 μg/day of folate from fortified foods or supplements
||400 μg/day of folate from fortified foods or supplements
||600 μg/day of folate from fortified foods or supplements
||800 μg/day of folate from fortified foods or supplements
|ULs for Pregancy
||800 μg/day of folate from fortified foods or supplements
|19 years and older
||1,000 μg/day of folate from fortified foods or supplements
|ULs for Lactation
||800 μg/day of folate from fortified foods or supplements
|19 years and older
||1,000 μg/day of folate from fortified foods or supplements
The IOM does specifically state that "individuals who are at risk of vitamin B12 deficiency …may be at increased risk of the precipitation of neurological disorders if they consume excess folate." Vitamin B12 deficiency can be due to dietary deficiencies (such as a complete vegan diet), pernicious anemia, gastrectomy, atrophic gastritis, bacterial infection, pancreatic insufficiency, and terminal ileal disease or resection (Medicine, 1998).
2017 American Society for Clinical Pathology (ASCP)/Choosing Wisely (Pathology, 2017)
The ASCP published a recommendation in 2017 in Choosing Wisely, an American Board of Internal Medicine (ABIM) initiative, where it clearly states the following: "Do not order red blood cell folate levels at all. In adults, consider folate supplementation instead of serum folate testing in patients with macrocytic anemia." It indicates that the drastic decrease in folic deficiency in both the U.S. and Canada after mandated folic acid supplementation in foods no longer requires either serum folate or red blood cell folate concentrations be tested. "While red blood cell folate levels have been used in the past as a surrogate for tissue folate levels or a marker for folate status over the lifetime of red blood cells, the result of this testing does not, in general, add to the clinical diagnosis or therapeutic plan."
2012 British Columbia Medical Association (Committee, 2012)
The Guidelines & Protocols Advisory Committee of the British Columbia Medical Association in conjunction with the Province of British Columbia released their guidelines concerning folate and folate deficiency. They state that "serum folate and red blood cell (RBC) folate tests are no longer being offered (except at Vancouver General Hospital and St. Paul’s hospital under limited indications and require approval from the respective Medical Biochemist on call)" because of the drastic decrease in folate deficiency in the province. "In two outpatient laboratories in British Columbia, 99.8% and 99.1% of folate tests were normal in 2010. … If folate deficiency is suspected, it is reasonable to give oral folic acid (0.4-1 mg/day) without doing laboratory investigation for deficiency, at least until the hemoglobin and mean corpuscular volume normalizes (or longer if the underlying cause cannot be eliminated)."
2003 National Pathology Alliance (of the United Kingdom) (Galloway & Rushworth, 2003)
The National Pathology Alliance of the United Kingdom in 2003 published in the Journal of Clinical Pathology its recommendation "that serum folate measurements provide equivalent information to red cell folate measurements."
2013, 2015 & 2017 American Association of Clinical Endocrinologists (AACE)/The American College of Endocrinology (ACE)/The Obesity Society (TOS) (Gonzalez-Campoy et al., 2013; Handelsman et al., 2015; Jellinger et al., 2017; Mechanick et al., 2013; National Guideline, 2013a)
In 2013, the AACE, ACE, and TOS issued joint guidelines regarding healthy eating for the prevention and treatment of metabolic and endocrine diseases in adults (Gonzalez-Campoy et al., 2013). Based on the data from the National Health and Nutrition Examination Survey (NHANES), they state "that patients with vitamin B12 deficiency had higher folate levels, were more likely to be anemic, and had more cognitive impairment that those with normal serum folate levels" [evidence level (EL) 2]. They evaluate the evidence concerning the link between folate and cardiovascular disease as EL4 and the link between NTDs and folate as EL1. With respect to pregnancy nutritional needs, they "should be assessed prior to conception to improve pregnancy outcome. … All women of childbearing age should consume at least 400 μg dietary equivalents of folate per day" [EL4] and that during pregnancy the daily amount should be increased to 600 μg [EL3].
Also, in 2013, the AACE, ACE, and TOS issued joint guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient (Mechanick et al., 2013; National Guideline, 2013a). Here, as part of a pre-operative bariatric surgery checklist that has a "Grade A" recommendation, they include "nutrient screening with irons studies, B12 and folic acid (RBC folate, homocysteine, methylmalonic acid optional) …consider more extensive testing in patients undergoing malabsorptive procedures based on symptoms and risks." With regard to patients who become pregnant after having a bariatric procedure, they recommend (with Grade D) having laboratory screenings done each trimester for folate deficiency along with iron, calcium, B12, and fat-soluble vitamins. With a Grade C, they state that "nutritional anemias resulting from malabsorptive bariatric surgical procedures might also involve deficiencies in vitamin B12, folate, protein, copper, selenium, and zinc and should be evaluated when routine screening for iron deficiency anemia is negative."
The AACE and ACE in 2015 released their Clinical Practice Guidelines for Developing a Diabetes Mellitus Comprehensive Care Plan (Handelsman et al., 2015). Concerning patients with diabetic nephropathy, they suggest that they "undergo annual or more frequent assessment of electrolytes." For those with anemia, iron, transferrin saturation (TSAT), ferritin, vitamin B12, and folate levels "should be further investigated" [EL4].
In 2017, the AACE and ACE released their guidelines for management of dyslipidemia and prevention of cardiovascular disease (Jellinger et al., 2017). Since bile acid sequestrant treatments such as cholestyramine can cause folate depletion in children, they recommend that children on such treatments supplement their diet with a multivitamin. They also note that folate, B6, and B12 supplementation can help mediate hyperhomocysteinemia, but that the supplements do not reduce risk of atherosclerotic cardiovascular disease.
2015 National Institute for Health and Care Excellence (NICE) (Centre, 2015)
The National Institute for Health and Care Excellence (NICE) of the Department of Health in the United Kingdom published its extensive guidelines concerning bladder cancer on February 25, 2015. Within the section concerning the follow-up treatment for muscle-invasive bladder cancer, it recommends a protocol after radical cystectomy that includes "monitoring for metabolic acidosis and B12 and folate deficiency at least annually."
2003 American Academy of Family Physicians (AFP) (Kaferle & Strzoda, 2009)
The AFP released recommendations concerning macrocytosis and macrocytic anemia in 2009. Of note, it states that "serum folate levels are not useful because they fluctuate rapidly with dietary intake and are not cost effective. RBC folate levels more accurately correlate with folate stores and should be performed if folate deficiency is suspected." It gives the following key recommendation (with evidence rating of "C" or "consensus, disease-oriented evidence, usual practice, expert opinion, or case series") to "obtain red blood cell folate level if other etiologies are not found (serum folate levels may be misleading)." In the evaluation of macrocytic anemia, it included a flowchart outlining the order of steps and tests to be taken, including when the RBC folate level should be checked. Patients exhibiting a mean corpuscular volume 100 fL and an abnormal peripheral smear showing megaloblastic features and a reticulocyte count under 2% should have their RBC folate level measured only if the vitamin B12 level is >400 pg. (Kaferle & Strzoda, 2009).
2001 American Academy of Neurology (AAN) (Knopman et al., 2001)
In 2001, the AAN updated its practice parameters for the diagnosis of dementia. Within the section concerning the comorbidities that should be screened in an initial assessment for dementia, it recommends folate testing along with complete blood count, serum electrolytes, B12, blood urea nitrogen/creatinine, syphilis serology, thyroid function, and glucose. It did note that as of that time, "no studies were identified that evaluated these recommendations" since the last practice parameters released in 1994.
2012 Kidney Disease Improving Global Outcomes (KDIGO) (McMurray et al., 2012)
KDIGO released its updated KDIGO Clinical Practice Guideline for Anemia in Chronic Kidney Disease in 2012. It gave a "not graded" recommendation for "patients with CKD and anemia (regardless of age and CKD stage), include the following tests in initial evaluation of the anemia:
- Complete blood count (CBC), which should include Hb concentration, red cell indices, white blood cell count and differential, and platelet count
- Absolute reticulocyte count
- Serum ferritin level
- Serum transferring saturation (TSAT)
- Serum vitamin B12 and folate levels"
It also states that "RBC folate levels can be measured when serum folate levels are equivocal or when there is concern that recent dietary intake may obscure underlying folate deficiency using serum levels alone."
2012 Australian National Blood Authority (Authority, 2012)
The Australian National Blood Authority of the National Health and Medical Research Council of Australia released its Patient Blood Management Guidelines: Module 2 Perioperative, an extensive set of guidelines concerning the perioperative patient. It includes a preoperative hemoglobin assessment that requires the preoperative tests for full blood count, iron studies (including ferritin), CRP, and renal function. If the patient is anemic and has a ferritin level > 100 mcg/L, then, it recommends checking "B12/folate levels and reticulocyte count" for possible anemia due to a chronic disease or inflammation. As a footnote, it includes: "check B12/folate if macrocytic or if there are risk factors for deficiency (e.g., decreased intake or absorption), or if anaemia is unexplained."
2013 American Society for Parenteral and Enteral Nutrition (ASPEN) & Society of Critical Care Medicine (SSCM) and 2016 ASPEN (Choban, Dickerson, Malone, Worthington, & Compher, 2013; National Guideline, 2013c, 2016)
In 2013, ASPEN and SSCM issued joint clinical guidelines concerning the nutrition support of hospitalized obese adults. With a "Recommendation: Weak" status, they recommended "in acutely ill hospitalized patients with history of these procedures [sleeve gastrectomy, gastric bypass, or biliopancreatic diversion ± duodenal switch], evaluation for evidence of depletion of iron, copper, zinc, selenium, thiamine, folate, and vitamins B12 and D is suggested, as well as repletion of deficiency states" (Choban et al., 2013). In 2016, ASPEN and SSCM issued their Guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient. The committee recommended that "evaluation for and treatment of micronutrient deficiencies such as calcium, thiamin, vitamin B12, fat-soluble vitamins (A, D, E, K), and folate, along with the trace minerals iron, selenium, zinc, and copper, should be considered" (National Guideline, 2016).
2013 Academy of Nutrition and Dietetics (AND) (National Guideline, 2013b)
The AND released its Oncology evidence-based nutrition practice guideline in 2013. On the "Assessment of Biochemical Data Medical Tests, and Procedures on Adult Oncology Patients" portion, the committee recommended with "Consensus, Imperative" that "the RDN [Registered Dietitian Nutritionist] should evaluate available data and recommend as indicated: biochemical data, medical tests and procedures of adult oncology patients" and included on its list is: "Nutritional anemia profile (hemoglobin, hematocrit, folate, B12, iron)". "Assessment of these factors is needed to effectively determine nutrition diagnoses and plan the nutrition interventions."
2013 Institute for Clinical Systems Improvement (ICSI) (National Guideline, 2013d)
The ICSI updated its guidelines on stable coronary artery disease in 2013. "An association between homocysteine levels and cardiovascular disease has been demonstrated. The NORVIT trial and HOPE 2 trial found that folate and vitamins B6 and B12 did not reduce the risk of recurrent cardiovascular events in patients with vascular disease. These supplements cannot be recommended as routine treatment in patients with stable coronary artery disease [High Quality Evidence]."
2015 European Crohn’s and Colitis Organisation (ECCO) (Dignass et al., 2015)
ECCO’s guidelines concerning irritable bowel disorders (IBD) included an extensive discussion on causes and treatments of anemia in IBD—both iron deficiency anemia and non-iron deficiency anemia. With an [EL 5], it states that "deficiencies of Vitamin B12 and folate should be treated to avoid anaemia. Serum levels of vitamin B12 and folic acid should be measured at least annually, or if macrocytosis is present. Patients at risk for vitamin B12 or folic acid deficiency [e.g., small bowel disease or resection] need closer surveillance. The recommended timelines are based on expert opinions and reflect common clinical practice, but do not apply to patients with extensive small bowel resection, extensive ileal Crohn’s disease, or ileal-anal pouch."
2013 American College of Gastroenterology (ACG) (Rubio-Tapia, Hill, Kelly, Calderwood, & Murray, 2013)
In its guidelines and recommendations concerning the diagnosis and management of celiac disease (CD) in 2013, the ACG recommended the following statement with Conditional recommendation, low level of evidence: "People with newly diagnosed CD should undergo testing and treatment for micronutrient deficiencies. Deficiencies to be considered for testing should include, but not be limited to, iron, folic acid, vitamin D, and vitamin B12."
2017 US Preventive Services Task Force (USPTF) (Bibbins-Domingo et al., 2017)
The USPTF in 2017 updated its 2009 recommendation regarding folic acid supplementation in women of childbearing age. The USPTF gives an "A" recommendation "that all women who are planning or capable of pregnancy take a daily supplement containing 0.4 to 0.8 mg (400-800 μg) of folic acid." The USPTF does not make any statement regarding folate screening for women of childbearing age.
- Authority, N. (2012). Patient blood management guidelines: module 2 perioperative. Canberra, Australia: National Blood Authority Retrieved from https://www.blood.gov.au/system/files/documents/pbm-module-2.pdf.
- Bibbins-Domingo, K., Grossman, D. C., Curry, S. J., Davidson, K. W., Epling, J. W., Jr., Garcia, F. A., . . . Tseng, C. W. (2017). Folic Acid Supplementation for the Prevention of Neural Tube Defects: US Preventive Services Task Force Recommendation Statement. Jama, 317(2), 183-189. doi:10.1001/jama.2016.19438
- Centre, N. C. G. (2015). Bladder cancer: diagnosis and management. (NG2). United Kingdom: National Institute for Health and Care Excellence Retrieved from https://www.nice.org.uk/guidance/ng2.
- Choban, P., Dickerson, R., Malone, A., Worthington, P., & Compher, C. (2013). A.S.P.E.N. Clinical Guidelines. Journal of Parenteral and Enteral Nutrition, 37(6), 714-744. doi:10.1177/0148607113499374
- Committee, G. P. A. (2012, 01/01/2012). Folate Deficiency - Investigation & Management. Retrieved from https://www2.gov.bc.ca/gov/content/health/practitioner-professional-resources/bc-guidelines/folate-deficiency
- Dignass, A. U., Gasche, C., Bettenworth, D., Birgegard, G., Danese, S., Gisbert, J. P., . . . Vavricka, S. (2015). European consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases. J Crohns Colitis, 9(3), 211-222. doi:10.1093/ecco-jcc/jju009
- Finer, S., Saravanan, P., Hitman, G., & Yajnik, C. (2013). The role of the one‐carbon cycle in the developmental origins of Type 2 diabetes and obesity. Diabetic Medicine, 31(3), 263-272. doi:10.1111/dme.12390
- Galloway, M., & Rushworth, L. (2003). Red cell or serum folate? Results from the National Pathology Alliance benchmarking review. J Clin Pathol, 56(12), 924-926.
- Gonzalez-Campoy, J. M., St Jeor, S. T., Castorino, K., Ebrahim, A., Hurley, D., Jovanovic, L., . . . Thomas, K. T. (2013). Clinical practice guidelines for healthy eating for the prevention and treatment of metabolic and endocrine diseases in adults: cosponsored by the American Association of Clinical Endocrinologists/the American College of Endocrinology and the Obesity Society. Endocr Pract, 19 Suppl 3, 1-82. doi:10.4158/ep13155.Gl
- Gregory, I. I. I. J. F., Swendseid, M. E., & Jacob, R. A. (2000). Urinary Excretion of Folate Catabolites Responds to Changes in Folate Intake More Slowly than Plasma Folate and Homocysteine Concentrations and Lymphocyte DNA Methylation in Postmenopausal Women. The Journal of Nutrition, 130(12), 2949-2952. doi:10.1093/jn/130.12.2949
- Handelsman, Y., Bloomgarden, Z. T., Grunberger, G., Umpierrez, G., Zimmerman, R. S., Bailey, T. S., . . . Zangeneh, F. (2015). American association of clinical endocrinologists and american college of endocrinology - clinical practice guidelines for developing a diabetes mellitus comprehensive care plan - 2015. Endocr Pract, 21 Suppl 1, 1-87. doi:10.4158/ep15672.Gl
- Imbard, A., Benoist, J.-F., & Blom, H. J. (2013). Neural Tube Defects, Folic Acid and Methylation. International Journal of Environmental Research and Public Health, 10(9), 4352-4389. doi:10.3390/ijerph10094352
- Initiative, F. F. (2018, March 2018). Global Progress of Industrially Milled Cereal Grains. Retrieved from http://www.ffinetwork.org/global_progress/
- Jellinger, P. S., Handelsman, Y., Rosenblit, P. D., Bloomgarden, Z. T., Fonseca, V. A., Garber, A. J., . . . Davidson, M. (2017). AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF DYSLIPIDEMIA AND PREVENTION OF CARDIOVASCULAR DISEASE. Endocr Pract, 23(Suppl 2), 1-87. doi:10.4158/ep171764.Appgl
- Joelson, D. W., Fiebig, E. W., & Wu, A. H. (2007). Diminished need for folate measurements among indigent populations in the post folic acid supplementation era. Arch Pathol Lab Med, 131(3), 477-480. doi:10.1043/1543-2165(2007)131[477:Dnffma]2.0.Co;2
- Kaferle, J., & Strzoda, C. E. (2009). Evaluation of macrocytosis. Am Fam Physician, 79(3), 203-208.
- Knopman, D. S., DeKosky, S. T., Cummings, J. L., Chui, H., Corey-Bloom, J., Relkin, N., . . . Stevens, J. C. (2001). Practice parameter: diagnosis of dementia (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology, 56(9), 1143-1153.
- Marshall, T., Williams, J., & Williams, K. M. (1991). Electrophoresis of serum isoenzymes and proteins following acute myocardial infarction. J Chromatogr, 569(1-2), 323-345.
- McMurray, J., Parfrey, P., Adamson, J. W., Aljama, P., Berns, J. S., Bohlius, J., . . . Ganz, T. (2012). Kidney disease: Improving global outcomes (KDIGO) anemia work group. KDIGO clinical practice guideline for anemia in chronic kidney disease. Kidney International Supplements, 2(4), 279.
- Mechanick, J. I., Youdim, A., Jones, D. B., Garvey, W. T., Hurley, D. L., McMahon, M., . . . Brethauer, S. (2013). Clinical Practice Guidelines for the Perioperative Nutritional, Metabolic, and Nonsurgical Support of the Bariatric Surgery Patient—2013 Update: Cosponsored by American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery(). Obesity (Silver Spring, Md.), 21(0 1), S1-27. doi:10.1002/oby.20461
- Medicine, I. o. (1998). The National Academies Collection: Reports funded by National Institutes of Health. In Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington (DC): National Academies Press (US)
- National Academy of Sciences.
- National Guideline, C. (2013a). Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient - 2013 update: cosponsored by American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic and Bariatric Surgery.
- National Guideline, C. (2013b). Oncology evidence-based nutrition practice guideline.
- National Guideline, C. (2013c). A.S.P.E.N. clinical guidelines: nutrition support of hospitalized adult patients with obesity.
- National Guideline, C. (2013d). Stable coronary artery disease.
- National Guideline, C. (2016). Guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.).
- Pathology, A. S. f. C. (2017, 10/19/2017). Do not order red blood cell folate levels at all. In adults, consider folate supplementation instead of serum folate testing in patients with macrocytic anemia. Twenty Things Physicians and Patients Should Question. Retrieved from http://www.choosingwisely.org/clinician-lists/ascp-do-not-order-red-blood-cell-folate-levels/
- Prevention, C. f. D. C. a. (1992). Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. MMWR Recomm Rep, 41(Rr-14), 1-7.
- Rothenberg, S. P., da Costa, M. P., Sequeira, J. M., Cracco, J., Roberts, J. L., Weedon, J., & Quadros, E. V. (2004). Autoantibodies against Folate Receptors in Women with a Pregnancy Complicated by a Neural-Tube Defect. New England Journal of Medicine, 350(2), 134-142. doi:10.1056/NEJMoa031145
- Rubio-Tapia, A., Hill, I. D., Kelly, C. P., Calderwood, A. H., & Murray, J. A. (2013). ACG clinical guidelines: diagnosis and management of celiac disease. Am J Gastroenterol, 108(5), 656-676; quiz 677. doi:10.1038/ajg.2013.79
- Schrier, S. L. (2018a, 01/05/2018). Causes and pathophysiology of vitamin B12 and folate deficiencies. Retrieved from https://www.uptodate.com/contents/causes-and-pathophysiology-of-vitamin-b12-and-folate-deficiencies
- Schrier, S. L. (2018b, 05/11/2018). Clinical manifestations and diagnosis of vitamin B12 and folate deficiency. Retrieved from https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-vitamin-b12-and-folate-deficiency
- Shojania, A. M., & von Kuster, K. (2010). Ordering folate assays is no longer justified for investigation of anemias, in folic acid fortified countries. BMC Research Notes, 3, 22-22. doi:10.1186/1756-0500-3-22
- Supplements, N. O. o. D. (2018, 03/02/2018). Folate Dietary Supplement Fact Sheet. Retrieved from https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/
- Wu, A., Chanarin, I., Slavin, G., & Levi, A. J. (1975). Folate Deficiency in the Alcoholic—its Relationship to Clinical and Haematological Abnormalities, Liver Disease and Folate Stores. Br J Haematol, 29(3), 469-478. doi:10.1111/j.1365-2141.1975.tb01844.x
||Folic acid; serum
||Folic acid; RBC
|ICD-10 Diagnoses Codes
||Other Megaloblastic Anemias, (NEC)
||Nutritional anemia, unspecified
||Dietary folate deficiency anemia
||Drug-induced Folate Deficiency Anemia
||Other Folate Deficiency Anemias
||Folate Deficiency Anemia, Unspecified; Folate Deficiency Anemia, NOS
||Other specified diseases of blood and blood-forming organs
||Deficiency of other specified B group vitamins
||Other long term (current) drug therapy
Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each Policy. They may not be all-inclusive.
This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross and Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.
"Current Procedural Terminology © American Medical Association. All Rights Reserved"
History From 2018 Forward
Updating review date. No other changes made