In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) is a measure of the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration.
This web application has been developed using R language and Shiny framework to calculate the Lethal Dose/Concentration by fit a Generalized Linear Model (GLM) assuming error distribution is binomial; it can apply three different link functions for probability transformation: Probit, Logit, and Complementary log-log.
User can upload an Excel spreadsheet file includes data of (Sample Data File):
- Number of subjects (e.g. total number of insects).
- Responded number (e.g. insects got killed).
- Explanatory variate (e.g. dose).
Analysis parameters includes:
- Effective (or lethal) dose/concentration (default is 50% and accepted value is in the range [0 – 100]).
- Level of confidence interval (default is 80% and accepted value is in the range [0 – 100]).
- Link function (default is “Probit” and available options includes also “Logit” and “Complementary log-log”).
- Take logs of explanatory (default is “None” and available transformations includes log base 10 and log base e).
Estimate of the Lethal Dose/Concentration, standard errors, fitted model parameters, and summary statistics. Further output can be obtained from the “Graphics Output” tab, which draws a graph of the fitted model showing the relationship of the response with the explanatory variable, including the confidence interval and LD cutting line for selected effective dose/concentration.
If there is a grouping factor (e.g. different types of pesticides), the analysis will be performed for each grouping level separately.
You can demonstrate an online demo of this application available here: https://icarda.shinyapps.io/ld50/
More information can be found in the following book chapter:
Singh, M., Al-Khatri, S., El-Shamaa, K., and Niane, A.A. 2018. Statistical Design and Analysis of Date Palm Insect Pest Management Experiments. In M. El Bouhssini and J.R. Faleiro (Editors), Date Palm Pests and Diseases Integrated Management Guide (pp. 20-39). ISBN 978-9291275052. Abu Dhabi. [link]