Clinical utility of serum folate measurement in tertiary care patients: Argument for revising reference range for serum folate from 3.0ng/mL to 13.0ng/mL

摘要

Objective Assess the need for folate testing, frequency of corrective action, and determine reference level for serum folate. Methods Serum folate levels in 5313 samples from 4448 patients, and clinical data were reviewed for patient characteristics and for (a) evidence of corrective action in patients with serum folate values <5.5ng/mL, and (b) differences in patients with serum folate levels 25.7ng/mL. Results The prevalence of serum folate levels, in patients, <3.0, <4.0, <5.5, <7.0 and <13.0ng/mL was 0.58%, 1.55%, 4.9%, 9.98% and 43.21% respectively. Patients with serum folate levels 25.7ng/mL the sample was collected after supplementation with folic acid. Of the 128 patients with serum folate <5.5ng/mL documentation of supplementation was present in only 38.9%. Conclusions Serum folate levels are below the current “normal” level of 3.0ng/mL in a larger proportion of tertiary care patients than that reported for ambulatory patients. In patients with folate deficiency, corrective action is lacking in >60% of the patients. Since serum folate levels ≥13.0ng/mL are needed for optimal prevention of neural tube defects in the embryo/fetus, we propose that normal serum folate level should be designated to be ≥13.0ng/mL. Highlights ? We examined prevalence of serum folate levels in two tertiary care hospitals. ? Folate de?ciency is more prevalent in tertiary care patients than in ambulatory ones. ? Serum folate level determined at admission, is a surrogate for nutritional status. Optimal prevention of neural tube defects requires serum folate level≥13.0ng/mL.