Background: Vitamin B12 status is assessed primarily by measuring total serum B12 using competitive binding methods. The lack of availability of a standard material and high-level reference measurement procedure affect the trueness of B12 results; this results in variation between methods. This study aimed to determine the reference intervals for vitamin B12 on three routine analytical platforms.
Method: A prospective reference population of healthy individuals was recruited according to the IFCC CRIDL criteria. Vitamin B12 samples were measured on Roche, Beckman and Siemens analytical platforms.
Results: In total, 300 adult subjects were recruited; the central 95th centile values for B12 for Roche (190-678 ng/mL) and Siemens (181-562 ng/mL) analytical platforms were in a close agreement. Beckman DXi, however, showed a significantly lower reference limit (110-562 ng/mL). All reference intervals are in keeping with previously published data but some are not in agreement with manufacturer provided reference interval.
Conclusion: As the quality of the reference intervals plays a significant role in clinical outcome, it is of great importance that laboratories use a method-specific reference interval and if possible, locally derived reference intervals until further method standardization occurs.
Keywords: Reference interval; analytical methods; vitamin B12.