Don’t order red blood cell folate levels at all. In adults, consider folate supplementation instead of serum folate testing in patients with macrocytic anemia.
|Rationale and Comments:||Since 1998, when the United States and Canada mandated that foods with processed grains be fortified with folic acid, there has been a significant decline in the incidence of folate deficiency. For the rare patient suspected of having a folate deficiency, simply treating with folic acid is a more cost-effective approach than blood testing. 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.|
|References:||• Joelson DW, Fiebig EW, Wu AH. Diminished need for folate measurements among indigent populations in the post folic acid supplementation era. Arch Path Lab Med. 2007; 131(3):477-480.
• Ray, JG, Vermeulen MJ, Boss SC, Cole DE. Declining rate of folate insufficiency among adults following increased folic acid food fortification in Canada. Can J Public Health. 2002;3(4):249-253.
• Latif T, His ED, Rybicki LA, Adelstein DJ. Is there a role for folate determinations in current clinical practice in the USA? Clin Lab Haematol. 2004;26(6):379-383.
• Shojania AM, VonKuster K. Folate assays are no longer useful diagnostic tools in medical practice. Blood. 2005;106(11 pt1):12b.
• Shojania AM. Folate assays are no longer useful as screening tests for malabsorption syndrome. Now, iron and B12 deficiency are more common than folate deficiency in adults with untreated celiac disease. Blood. 2005;106(11 pt1): 12b.