Evidence Based Laboratory Medicine: linking tests to outcome s

There are challenges surrounding the appropriate us e of diagnostic tests. There is the fundamental issu e regarding the type and quality of evidence required to demonstrate clinical and economic effectiveness . Central to this issue is ensuring that studies addres s the right question and that the study design is robus t with measurement of appropriate outcomes for th e clinical questions being asked. Several systemati c reviews to date indicate that these requirements ar e not being met. However, there is also an importan t constraint in study design because the outcome tha t one wishes to measure is dependent not only on th e use of the diagnostic test but also on the implement a - tion of an action plan, eg therapeutic intervention that follows from receipt of the test result. Thes e points are discussed, identifying some of the outcom e measures that can be used to judge effectiveness of a There are many challenges facing laboratory med i - cine today, which offer both opportunities and con - straints. Many of the opportunities derive from th e wealth of basic and applied research in clinical med i - cine which enhances our knowledge of the patho - physiology of diseases and begins to define health and wellbeing. This base of knowledge also leads to the development of new therapies and the recognition of new disease markers. The endeavours of the an a - lytical and manufacturing scientists then produce s innovative analytical methods and devices that enabl e the marker to be used for the screening, diagnosis and management of disease. The activities of the diagno s - tics and pharmaceutical industries ensure a constan t supply of new and innovative technologies . It might be argued that the changes seen in popul a - tion demographics with an ageing population, with morbidity and mortality statistics affected by othe r factors such as changes in lifestyle, also provides an opportunity. However, in that these changes can also increase the demand on the laboratory services they may be considered as a constraint . Similarly changes in clinical practice might be seen as an opportunity - in, for example, a greater use o f point of care testing. On the other hand there is no doubt that changes in clinical practice with the adven t of more rapid triage strategies, more one-stop clinic s and the evolution of ambulatory care and diagnosti c facilities, will place greater demands on the labor a - tory services, with significant reduction in result turn - around times required. Changes in clinical practic e are also associated with a constant drive to improv e the quality of services, and outcomes, for the patient . There is no doubt that the overall increase in demand for laboratory services is a major constraint when viewed in the context of limited, and sometime s capped, resources. It is uncommon for service leve l agreements between purchasers and providers to hav e the level of sophistication to take account of change s in workload. Consequently, an increasing workload i s often reflected in improved productivity of equipmen t and staff. This in turn drives down the cost per test - in some respects a laudable outcome, but inevitably leading to cost constraints and limiting the opportu - nity for investment in the development of new test s