Clinical chemistry, instrumentation

E264 Glick, M.R., Ryder, K.W. and Jackson, S.A. (1986). Graphical comparisons of interferences in clinical chemistry instrumentation. Clin. Chem. 32, 470-475. 

E339 Glick, M.R. and Ryder, K.W. (1987). Rating clinical chemistry instruments. Evaluation of the effect of interferences under standard conditions. Clin. Chem. 33, 964, Abstr. 408. 

In modern automated clinical chemistry instruments, the relation between analyte concentration and signal is often very stable so that calibration is necessary infrequently (e.g., at intervals of several months). Built-in process control mechanisms may help ensure that the relationship remains stable and indicate when recalibration is necessary. In traditional chromatographic analysis (e.g., high-performance liquid chromatography [HPLC]), on the other hand, it is customary to calibrate each analytical series (run), which means that calibration is carried out daily. Aronson et aft established a detailed simulation model of the various factors influencing method performance with focus on the calibration function. 

The future of ISEs in the clinical chemistry instrumentation is quite exciting. As described in subsequent sections of this article, the coupling of enzyme and immunological reagents to ISE detectors to form bioelectrode systems appears to offer manufacturers a new approach toward the detection of metabolites such as creatinine and urea directly in blood and urine samples. Ultimately, such biosensors will be placed into complete electrode-based automated clinical analyzers. In addition, continued research on new membrane formulations, particularly liquid membrane ionophore systems, will result in the development of addition electrodes which can be incorporated into current analyzer systems to expand the electrolyte menu. Indeed, recent efforts have indicated that membranes selective fi)r bicarbonate (F5) and lithium (Z2) are likely additions in the near future. 

We are also at a point in time where recently developed bioselective electrode systems will gain widespread use in clinical chemistry instrumentation as well as for basic biomedical research efforts in which in situ assays of biochemical species are required. While enaiyme electrodes offer the most hope with regard to highly selective assay techniques, continued research into the development of new tissue and bacterial membrane electrode systems may lead to devices with improved operational lifetimes and sensitivity to compounds not amenable to enzymatic analysis (e.g., antibiotics). Indeed, considering the recent strides made in recombinant DNA technology, it may... 

M. L. Glick and K. W. Ryder, Interferographs Users Guide to Interferences in Clinical Chemistry Instruments, Science Enterprises, Indianapolis, IN, 1987. 

AUTOMATED INSTRUMENTATION - CLINICAL CHEMISTRY] (Vol3) -pumps [PUMPS] (Vol 20)... 

Clinical chemistry analy2ets ate automated instmments used for measuring concentrations of the various chemical constituents of blood or other body fluids. For a discussion of the related category of instmments used for the measurement of blood cell parameters, see Automated instruments, HEMATOLOGY. 

We have found that the use of serum standards for standardizing the instrument in the laboratory is useful. However, the serum standards cannot be used for urines. In urines, one runs into other problems and needs to use aqueous standards. Therefore, at present, while atomic absorption is the instrument of choice, there is much to be desired for the determination of calcium and magnesium in the routine laboratory of clinical chemistry. 

The multitest analysers simultaneously measure more than one constituent in each sample and are often designed to meet the needs of a particular type of laboratory, e.g. clinical chemistry departments. The instruments offer different test combinations (menu) but these are often determined by the manufacturer, leaving little opportunity for modification within the laboratory. 

The sequential multiple analysers (SMAs) were later developments and they were much more complex in design and included a computer. They could analyse each sample for several constituents simultaneously, the number of channels determining this capacity, i.e. 6, 12 or 20. These instruments were developed primarily for hospital clinical chemistry laboratories to allow an overall assessment of the chemical composition of blood samples. They have now been superseded by other types of analysers. 

In clinical chemistry every method is different. Even the instrument used has certain values for controls such that different values result from the analytical process."... 

Instrumentation in Clinical Chemistry Peter M. G. Broughton and John B. Dawson... 

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