Bacterial killing assays in ecoimmunology require cross-validation by agreement statistics

The bacterial killing assay (BKA) is a simple assay that assesses the ability of the constitutive immune system, typically the plasma-based immune system, to clear pathogens in vitro. Historically, this has been accomplished through counting bacterial colonies on solid agar plates (CFU-based), however, over the last 15 years, a technique that makes use of optical density (OD-based) has been steadily gaining in popularity. Although cross-validations have been performed between these two methods in the past, they only compared measurements of growth (colony counts and absorbance) using correlation statistics with plasma. We performed our own method cross-validation using first blood cells (red and white blood cells with plasma removed) and then plasma, and compared measurements of growth and bactericidal ability using both correlation and agreement statistics. Our results found that while there was a weak correlation between colony counts and absorbance at 300nm, we found poor agreement b..., , # Bacterial killing assays in ecoimmunology require cross-validation by agreement statistics Dataset DOI: [10.5061/dryad.z8w9ghxtb](https://doi.org/10.5061/dryad.z8w9ghxtb) ## Description of the data and file structure This dataset contains the experimental data obtained during a bacterial killing assay performed on blood cells and plasma isolated from the Mojave desert tortoise. The first dataset is the cell-based bacterial killing assay (BKA) and is split into three separate sheets: the first contains sampling season, tortoise ID, colony counts, and optical density (OD) at 300nm; the second contains sampling season, tortoise ID, colony forming unit (CFU)-based bactericidal ability, OD300-based bactericidal ability, the difference in bactericidal ability between the two methods, and the mean bactericidal ability of the two methods; the final sheet contains tortoise ID, incubation temperature, CFU-based, OD300-based, and OD600-based bactericidal ability, the difference in bactericida..., ,