MAXIMIZING THE COST-EFFICIENCY OF ASSAY PROCEDURES

Cortisol concentrations were measured in cattle plasma and pig muscle juice samples obtained from groups of animals slaughtered at different abattoirs. Statistically significant (P < 0.001) differences were obt ained for between-abattoir comparisons for both the cattle and pig sam ples. Cortisol concentrations were determined using a radio-immunoassa y kit. In accordance with the instructions, assays were performed in d uplicate. An analysis of variance indicated that the use of a single d etermination on more samples, instead of duplicate determinations of f ewer samples, would have led to an important increase in accuracy for detecting differences between means. It would have been more cost-effi cient to collect additional samples and perform one assay only on each sample.