Preanalytical considerations in the design of clinical trials and epidemiological studies

Whatever the study goals may be, the quality of study outcomes will depend heavily on the quality of the samples obtained and subsequent analysis. Since the largest component of total error in the clinical laboratory has been found to be associated with the preanalytical phase, it is probably safe to assume that the same conclusion applies to clinical trials and epidemiologic studies. Since conclusions may be drawn on diagnosis, staging, prognosis, stratification, etc., the results of a study could actually result in clinical guideline changes; thus, we must assure the highest standards in sample integrity.