Reference values for serum folate and vitamin B12 in a Spanish population using an electrochemiluminiscent method

Background

Despite being the most widely used medical decision-making tool, reference intervals are not usually determined by clinical laboratories, due to the highly demanding activities and costly process it involves. However, scientific societies encourage individual clinical laboratories to establish their own reference values. This is especially important in the cases of folate and vitamin B₁₂, due to strong differences in vitamin status among different populations.

Objective

Our aim is to establish reference intervals for folate and vitamin B₁₂ levels in a healthy blood donor population using an electrochemiluminiscent method (ROCHE DIAGNOSTICS).

Method

Folate and vitamin B₁₂ levels were measured in 141 healthy blood donors aged between 18 and 65 years. Biochemical analyses were performed using a Modular E170 analyzer (ROCHE DIAGNOSTICS) and an electrochemiluminiscent method. Reference intervals were calculated with a non-parametric percentile method following the CLSI guidelines.

Results

There were not significant differences in folate or cobalamin levels between age or sex subgroups. The limits of the reference interval for folate were 2.2 and 18 ng/mL (5–40.7 nmol/L), and 213.8 and 763.3 pg/mL (158.2–564.8 pmol/L) for vitamin B₁₂. These intervals differed from those claimed by the manufacturer.

Conclusions

Our results emphasize the convenience of building reference values based on the population served by the laboratory, in order to unequivocally rule out deficiencies of folate or vitamin B_12.