Application of ISO 5725 to evaluate measurement precision of distribution within the lung after intratracheal administration

Intratracheal administration testing is an in vivo screening method for evaluat- ing the pulmonary toxicity of nanomaterials. However, no public test guidelines currently exist for this method. Thus, the present study conducts an inter- laboratory comparison study and quantitatively analyses the results. More precisely, (1) it tests whether or not the true between-laboratory variances are greater than zero by applying one-way analysis of variance (ANOVA), (2) it compares the sizes of the true between-laboratory variances and the repeata- bility variances through the F-test and (3) it calculates the statistical powers of the statistical tests in (1) and (2). The following results were obtained: (1) the true between-laboratory variances were greater than zero, (2) the true between-laboratory variances were not larger than the repeatability variances and (3) the sample sizes of the experiments provided sufficient statistical power for detecting the expected variances, if present. We propose that to elucidate the sizes of the true between-laboratory variances, we should not only quan- tify their sizes, but should also compare them to those of the repeatability variances.