Integrated biomarker responses: a further improvement of IBR and IBRv2 indexes to preserve data variability in statistical analyses.

Abstract

In biomonitoring and laboratory studies, it is typical to measure a battery of molecular, biochemical, and cytogenetic biomarkers to evaluate the effects of xenobiotics in biota. However, summarizing the results of several biomarkers to inform laypersons and environmental agencies is still a challenge for researchers and environmental specialists. To address this issue, researchers have developed indexes such as the Integrated Biomarker Responses (IBR) and Integrated Biomarker Response version 2 (IBRv2) to summarize all biomarkers responses into a single value. Unfortunately, these indexes do not preserve the original biological variability, which hampers subsequent statistical analyses. In this study, we created new versions of IBR and IBRv2, which preserve individual data variability and can be used in typical statistical analyses. The new Integrated Biomarker Responses individual (IBRi), Integrated Biomarker Responses version 2 individual (IBRv2i) and Weighted Integrated Biomarker Responses version 2 individual (Weighted IBRv2i) indexes correlated with the original IBR and IBRv2 indexes and were able to detect differences among experimental groups in a simulated and case studies. Using the IBRi, IBRv2i, or Weighted IBRv2i indexes is advantageous because they maintain the data variability of the experimental groups and can be analyzed using hypothesis testing statistics like any other parameter. Additionally, this approach can help translate technical scientific terminology into a more accessible language suitable for environmental governmental agencies and decision-makers.