Test av litiumheparinplasma fo?r analys av folat med Siemens Advia Centaur® XP samt effekt av inomhusbelysning o?ver tid
Background: Folate is a water - soluble vitamin necessary for normal DNA synthesis among other mechanisms. Folate deficiency can cause megaloblastic anemia resulting from abnormal erythrocyte d evelopment. At the Department of Clinical Chemistry, Linköping, analysis of folate is performed with Siemens ADVIA Centaur® XP which uses an immunochemical method with chemiluminimetric detection. Currently, the assay is conducted on serum, is poured off and frozen after 48 h and treated with light protection because folate is considered to be light sensitive.Methods: This study tested lithium heparin plasma for analysis of folate with Siemens ADVIA Centaur® XP with the aim to be able to perform a package of analyzes in anemia investigation from the same collection tube. Furthermore, the stability of folate was studied for up to 168 h and examined regarding light sensitivity.Results: Statistically significant higher values were obtained in the analysis of folate in lithium heparin plasma than folate in serum (p < 0,001). Serum folate was found to be stable up to 168 h and plasma folate was stable up to120 h. No statistically significant difference was found either between the serum or plasma folate regarding light exposure.Conclusion: Folate cannot be analyzed on lithium heparin plasma with the same reference range for serum folate, and further studies and a new reference range for plasma folate are needed to decide whether folate allows to be analyzed in plasma. Collection tubes for determination of folate in serum do not need to be light protected or poured off and frozen after 48 h which simplifies sample handling, reduces errors by relabeling and results in increased prospective automatized handling.