title: Central laboratory sampling plans and quality control in clinical trials.
abstract: Central laboratories play an important role in many clinical trials. An important tool in aiding the interpretation of these data has been the use of quality control procedures, primarily achieved by having the central laboratory gather additional data from a subset of the trial participants and therefore obtain a measure of the central laboratory's precision. However, both the additional burden on patients as well as rising clinical trial costs demand that when this trial component is required, it be executed as efficiently as possible. The following analysis explores the relationship between both the number of individuals taking part in the quality assessment and the number of repeated intrapatient measurements on the efficiency of the quality control. This examination reveals that the efficiency of the quality control mechanism for central laboratories is dependent on the sampling scheme used to obtain the specimens, and, in general, a small confidence interval for the variance of reproducibility can be obtained when more than two intrapatient measurements are utilized. Confidence interval lengths are provided for several different combinations of interpatient and intrapatient measurements.
authors.affiliation: University of Texas School of Public Health, Houston 77030.
authors.forename: L A
authors.initials: LA
authors.lastname: Moyé
mesh_terms: D002986:Clinical Trials as Topic / Q000592:standards*; D006801:Humans; D011446:Prospective Studies; D011786:Quality Control; D015203:Reproducibility of Results