Trends in Clinical Chemistry

Focal Point: Analytical Chemistry : ILMAC Congress: October 14, 1999

Abstract

Analytical chemistry and clinical chemistry have come closer together over the past thirty years and increasingly profit from each other. Advances in elucidating the human genome and the genomes of viruses and microorganisms have made it possible to track down a disease to the level of the nucleic acids and the genetic code, and to identify a disease on the molecular level. Examples are given of the diagnosis of a complex of inherited diseases, the porphyrias, on a molecular basis and of the identification of a virus infection referred to as Bordetella Pertussis. In addition, the trend to on-site analysis, which can provide immediate information about the state of a patient, is contrasted with high-throughput analysis in central laboratory units. The second contribution deals with the logistics of point-of-care testing (POCT) and its technological prerequisites in Sweden.
In clinical chemistry, novel technologies are not primarily rated according to their originality but rather according to logistic considerations. These include economic factors, the time-elapse to information, the ease of quality assessment and the consequences of a positive result, i.e. of a result which exceeds the decision limit separating sick patients from the population of healthy individuals. During the past 30 years, since 1968, the technical equipment used in clinical chemistry has been revolutionized and it has become much more widespread. Currently major advances are being made in Point-of-Care Testing (POCT) and Home Care Testing where Laboratory Information Technology (LIMS) and global exchanges via the Ethernet and Internet have become important links in the information chain. Automation has been driven forward so that it is now possible to automate the separation steps, the sample pretreatment and sample distribution steps at high throughput. When performing special analyses where the analytical procedure cannot be implemented using high-throughput instruments, it has been beneficial to apply advances in analytical chemistry to clinical chemistry. Such advances include analytical techniques such as mass spectrometry, gas chromatography, and HPLC. In some special domains where analytical technologies are applied to provide specific information based on, for example, the separation and identification of peptides and proteins via, for instance, two-dimensional electrophoresis, blotting techniques or PCR-relied analyses, clinical chemistry is even more advanced than analytical chemistry. However, in clinical chemistry, using an analytical technique is only justified if a positive result can lead to a useful medical treatment and to an improvement in the state of health of the patient.
At the same time, the work that aims to describe the entire human genome by the year 2003 [1] has stimulated, and continues to stimulate, practices and techniques that allow gains in information to be tracked down to the source of a disease. It has also become possible in some cases to predict the probability of being affected by an 'illness', which is based on a genetic predisposition, before symptoms break out. This means that prevention can be more effective, so that people liable to be affected by a hereditary disease can be trained to adjust their everyday behavior and to try to prevent the illness. In microbiology, it is now possible with PCR and electrophoresis to identify microorganisms in a timeframe of single days instead of the days and weeks needed to cultivate microorganisms.
In the following, the authors provide insights into the organization of point-of-care testing (POCT) and describe some specific techniques which should solve some problems currently facing clinical chemistry.