Case series

A case series is a type of observational study in medicine. In it a group of patients with a particular disease is considered, without compromising in the study, special measures, such as a study-specific therapy, done ( non-interventional study).

Case series have the lowest level of evidence of evidence-based medicine. For example, on rare diseases with the controlled randomized trials can not be investigated, but they are sometimes the best way to assess the effectiveness of an intervention.

Case series can be divided in retrospectively and prospectively compiled. In a retrospective case series compiled raises the question of the comparability of diagnostic criteria, for example, while those aspects of prospective studies can be determined in advance.