The pharmaceutical industry is obliged to collect data to quantify the effects of new medications on the biochemical and hematological profiles of human volunteers and patients, in addition to assessing clinical parameters which measure efficacy. The aim of collecting these laboratory data is to ensure that their effects on the human system are understood as completely as possible (safety aspects) and, in some cases, laboratory data may also be an indicator of the efficacy for the drug under investigation.In the choice of laboratory contract research organizations (CROs), sponsors attach great importance to the participation certificates of laboratories in a proficiency testing (PT) or external quality assessment (EQA) program. The philosophy behind this is that PT reflects routine quality. This paper situates EQA and PT within a concept of total quality management. Some examples, illustrating the relationship between EQA and routine performances, are provided. Finally, pertinent questions concerning EQA ...