Statistical aspects of health monitoring of laboratory animal colonies

Abstract

Sample size, sampling frequency and the importance of random sampling in health monitoring of colonies of laboratory animals are discussed and the terms nosographic sensitivity (N1), nosographic specificity (N2), diagnostic sensitivity {D1}, and diagnostic specificity (D2) are explained. It is concluded that test systems with a diagnostic specificity above 0.95 should be chosen, while a low nosographic sensitivity can be accepted, if the sample size (S) is calculated from the formula

in which p is the prevalence.