Stability of Biochemical Analytes in Reconstituted Lyophilised Controls; Deionised Water VS Ethanediol

Abstract

This paper compares the stability of commercial accuracy controls reconstituted with 15%(V/V) ethanediol with the conventional method of reconstituting with deionsed water. Two vials of the same batch of Beckman Coulter lyophilised control was used for this study. One vial was reconstituted with deionsed water and the other with 15% (V/V) ethanediol. Each lot was aliquoted into several vials (0.3 ml each) and both preparations were stored at -200C. Assays for a total of 23 biochemical analytes were carried out using each lot on the same day. This exercise was done at regular intervals of time upto one month. Mean and %CV values for each analyte in each preparation was then calculated and the outcome analysed. The interassay %CV obtained for a majority of analytes during one month were less compared to controls reconstituted with deionsed water. These data strongly support that lyophilised controls reconstituted with 15% (V/V) ethanediol shows better stability compared to controls reconstituted with deionsed water. The outcome of this study confirms that commercial controls used in clinical laboratories shows less day to day variations and long term stability when reconstituted with 15% (V/V) ethanediol than with deionised water. Such a procedure will help clinical laboratories to use controls reconstituted with 15%(V/V) ethanediol economically for a longer period of time to save time, labour and cost on commercial controls.