Evaluation of clinical chemistry analytes from a single mouse using diluted plasma: effective way to reduce the number of animals in toxicity studies.

Clinical chemistry is an essential analytical tool in many areas of research, drug assessment and development, and in the evaluation of general health. A certain amount of blood is required to evaluate all blood analytes. Experiments where mice are used, it is difficult to measure all analytes due to the small amount of blood that can be obtained from a single animal. To overcome this problem, separate cohorts of animals are used in toxicity studies for hematology and biochemistry analysis. This requires the use of extra animals and additional resources. Hence interpretation of results derived from using these different animals can be unreliable. This study was undertaken to explore the possibility of using diluted plasma for measuring various biochemistry analytes. Plasma from mice was diluted to 3, 5 and 10-fold with Water for Injection, and various biochemistry analytes were analyzed using an automated analyzer. Results of diluted and undiluted plasma from the same mouse were compared. Most of the analytes from the diluted plasma were found to be well within the ranges of the undiluted plasma except for sodium, potassium and chloride. Diluting plasma to analyze some analytes also freed up undiluted plasma for analyzing electrolytes. In conclusion, in order to obtain reliable and interpretable data from a single mouse it is worthwhile considering diluting the plasma, which should reduce the number of animals used in an experiment.