ABSTRACT
Vitamin B12 (cyanocobalamin) is a water soluble hematopoietic vitamin that functions in somatic cell metabolism. Vitamin B12 is commonly measured by direct chemiluminescence immunoassay methods in routine biochemistry laboratories. Serum samples to be tested for vitamin B12 are recommended to be kept protected from light. On the basis of this information, we aimed to evaluate the effect of light and waiting time till analysis on vitamin B12 tests.
In total, 52 volunteers (27 women and 25 men) were included in our study. To prevent the effect of light, we prepared darkened tubes for blood collection. Simultaneously, two tubes of blood samples (one darkened and one normal) were drawn from each patient. The measurements were performed on the 0th and 12th hours using the Roche Hitachi Modular E 170 autoanalyser. The Mann-Whitney U test and Wilcoxon test were used, and p<0.05 was considered significant.
There were no significant differences in vitamin B12 levels between darkened and normal tubes on the 0th and 12th hours (p>0.05). In comparison with the baseline (0th hour), the percentage difference in darkened tubes were found to be significantly decreased on the 12th hour (p<0.05).
Our findings indicate that the need for the darkened tubes may be ignored when cost-effectiveness is considered. (JAREM 2015; 5: 14-6)
Keywords: Vitamin B12, immunoassay, preanalytic interference
