[50 years of clinical chemistry, first hand experience].

Approximately since 1945, progress in the field of photometric analysis also found its way into the laboratories of clinical chemistry. These techniques almost completely replaced the then prevailing gravimetric and titrimetric methods. At the same epoch, many of the biochemical reagents which up to then had to be prepared by the clinical laboratories themselves with great expenditure of work became commercially available. The increasing number of analytical orders could only be mastered thanks to the newly developed analyzers. Novel microliter techniques made it possible to diminish drastically the volumes of samples and reagents necessary. The radioimmunoassay opened up new analytical dimensions, the limits of detection and of quantification were expanded downwards to the picomol range. Soon afterwards, enzymes and/or fluorochromes were used as markers in immunoassays. The development of monoclonal antibodies constituted further important progress in this field. The latest revolutionary invention is doubtlessly the polymerase chain reaction (PCR), and related techniques. These methods are bound to bring about fundamental change not only in clinical chemistry but in the medical laboratory diagnostics in general.