The origin of clinical laboratories.

Clinical laboratories are a main attribute of clinical chemistry. Their historical development is therefore of great interest in the history of clinical chemistry. The results of a study are given which was undertaken to trace the establishment of clinical laboratories in central Europe, mainly in France, England and in the German-speaking countries. Presuppositions for the creation of these laboratories were: (i) The idea that the results of laboratory examinations can be used as "chemical signs" in medical diagnosis, and (ii) a new concept of disease which was the result of the "birth of the clinic" at the end of the 18th century. The study shows that the development of clinical laboratories began 200 years ago. Up to the end of the 19th century, three development phases can be distinguished: an early phase from 1790 to 1840, a phase of institutionalization from 1840 to 1855, and a phase of extension between 1855 and 1890. To characterize these three phases, the foundation of the laboratories, the layout of the laboratory rooms, their equipment and instrumentation, and the usual staff are described with the aid of typical examples.