The advent of modern instrumentation, with associated improvements in test reliability, together with appropriate internal quality control and external quality assurance measures, has led to substantial reduction in analytical errors within hemostasis laboratories. Unfortunately, the reporting of incorrect or inappropriate test results still occurs, perhaps even as frequently as in the past. Many of these cases will arise due to a variety of events largely outside the control of the laboratories performing the laboratory tests and primarily comprise preanalytical events related to patient collection and sample processing and postanalytical events related to the reporting and interpretation of test results. The current article provides an overview of these events and provides some suggestions on how they can be minimized or prevented to ensure that the test results the clinician receives actually represent the true clinical status of the patient under investigation rather than just reflecting the status of an (inappropriate) clinical sample received and tested. This article should be of interest to both laboratory scientists working in hemostasis and the clinicians that request such tests. The former, because these are ultimately responsible for the test results they provide to clinicians, and there is a duty of care to provide both accurate and precise results to enable clinicians to manage patients appropriately and to avoid the need to recollect and retest. The latter because unless clinicians gain an appreciation of these issues, they will not be in a position to best manage their patients.