[A review of concepts in health services access and utilization].

The purposes of this article are to review the concepts of health services access and utilization and to analyze how these concepts interrelate. Access is a complex concept (often used inaccurately) which changes over time and according to the context. Health services utilization is at the core of health systems functioning. Despite some disagreement, according to this review the prevailing perspective is that access is related to characteristics of services supply. Health care services utilization can be applied as a measure of access, but use of services depends on other factors. Individual and contextual factors influence the use of services. The article shows that the concept of access is becoming more comprehensive and is changing its focus from entry into the health system to outcome of care. Access is valued in relation to its impact on health and depends on the effectiveness of care delivered. As an outcome measure, access becomes multidimensional and difficult to operationalize. Finally, the article discusses how health determinants differ from those of health services utilization, which impacts directly on illness, but only indirectly on health.