Toxicology experimental design and conduct as measured by interlaboratory collaborative studies

Interlaboratory variability in certain acute toxicological procedures was discussed. Three collaborative studies have been performed. One study concerned a determination of acute peroral toxicity and 2 collaborative studies have involved eye and/or skin irritation. All have indicated that, while the majority of the laboratories produced relatively consistent results, some were definitely outliers and others were quite variable. Recommendations were made to counteract and correct this interlaboratory variability; it was suggested that these be accomplished before standardization of techniques be promulgated. A brief discussion was presented on the faulty conclusions that can result from improperly planned and executed repeated-dose toxicological studies. Furthermore, the estimation of risk at the low-response end of a dose-response curve was discussed. The relative variability of the measurement of the slope of such a curve was compared to the variability of the measurement of the midpoint. The danger of extrapolation of animal dose-response results, using a constant slope, was deprecated.