Endocrine Abstracts

This study aimed to establish the optimal cut-off decision point for Folate and B12 levels. Retrospective review of serum, RBC folate as well as B12 test results performed at our hospital for the period April 2012 up to May 2016 were analysed for concordance.

With data analysis of around serum folate and B12 20,000 results, the new cut-offs for low values are tentatively set to be 5.5 ng/ml and 178 pg/ml. The percentages of deficiencies in our patient population are calculated to be 1.6 and 1.8% for serum folate and B12 respectively, based on the new cut-offs. The new serum folate cut-off also harmonizes the percentage deficiency (5.9%) in selected patient population with both serum and RBC folate measured within 1 week (n=51).

While in an era of folate fortification, its deficiency in general population is expected to be very low (<1%). With the current reference cut-offs (serum folate 7.3 ng/ml, RBC folate 366 ng/ml), it is found that 5.8% of our patients’ population has low serum folate, 8.3% has low RBC folate. It is also noted that there is a discrepancy between the percentages of low serum and RBC folates resulted within one week from the same patients (n=51): 13.7% vs 5.9%. With B12 reference range of 211–911 pg/ml, 3.7% of our patients are found to be B12 deficient.

With the low percentage deficiency in our patient population the following recommendations will be proposed: first, RBC folate testing is not warranted because serum folate testing provides the same differentiating power. Second, due to the low percentages of deficiencies in folate or B12, empirical supplementation is recommended.