Karber Method for Estimating Median Lethal Concentrations in Toxicity Bioassays - Essay Example

Chronic testing extends over a longer period than the subchronic testing. The observation period for subchronic testing is about three months, while the observation period for chronic testing is about twelve to twenty-four months (Hamilton, 1977). Subchronic testing usually involves a lesser group of animals than chronic testing. While chronic testing could involve a large group of animals of about twenty for each sex (for rodents), sub-chronic testing could take about ten for each sex (for rodents) (Hamilton, 1977).

The name sub chronic testing is even an indicator that it involves a lower level of toxicity testing o chronic testing. In carrying out the toxicity experiment, there are several factors that should be considered in order to determine the most suitable toxicity method. It should be noted that, if a large group of animals is involved, the chronic testing method is preferred, but if it is only a few groups of animals, the sub chronic testing method is preferred over the chronic testing method.