Point-of-care analysis

There is a defined need for point-of-care analysis for certain tests, those for which results are needed quickly. For example, the length of time between symptom onset and initiation of treatment is critical for minimizing cardiac injury during a heart attack. The emergency care unit (ECU) is very dependent on quick blood test results to confirm a heart attack and render the appropriate care. Transporting samples to a laboratory to obtain results can be very inefficient. So ECUs may have a bedside enzyme analyzer requiring minimal operation. A blood sample may be inserted, a button pushed, and results obtained in less than one minute. 

Vrouwe, E. X., Luttge, R., Vermes, I., and van den Berg, A., Microchip capillary electrophoresis for point-of-care analysis of hthium. Clinical Chemistry 53, 117-123, 2007. 

A.J. Tudos, G.A.J. Besselink, and R.B.M. Schasfoort, Trends in miniaturized total analysis systems for point-of-care testing in clinical chemistry. Lab on a Chip 1, 83-95 (2001). 

As occurred with the other antibiotics, commercial immunoassay formats, also available as kits for tetracyclines and penicillins such as the Parallux, the LacTek, or the Charm II, have also been placed on the market for the analysis of sulfonamides (see Table 4). Thus, the Parallux detects sulfamethazine and sulfadimethoxine in raw milk with a LOD of 10 pg L1. The Charm II detects almost all sulfonamides in honey and milk with a LOD in the range from 1 to 10 pg L, whereas LacTek is able to detect sulfamethazine. Moreover, the 5101SULlp and 5101SUDAlp tests reach LOD values for sulfamethazine and sulfadiazine of around 0.2 pg L 1 and they have been applied to the analysis of urine, milk, and plasma. These tests have proved to be efficient as a point of care for on-site applications on farms. Moreover, commercially available antibodies can be found from several sources such as Silver Lake Research, US Biological, Cortex Biochem. Inc., Accurate Chemical Scientific, Fitzgerald Industries International Inc., and Biotrend Chemikalien GmbH. 

Commercial application of the dendrimer-based reagent technology has been demonstrated by the successful development of The Stratus CS STAT fluorometric analyzer [5] marketed by Dade Behring Inc. This rapid automated point of care immunoassay system provides quantitative analysis of whole blood or preprocessed plasma samples via unit use assay test packs. Up to four test packs can be introduced for each sample. All reagents [5-9] required for specimen analyses are contained within the test packs. 

These versatile microfluidic systems will provide new tools for clinical diagnostics and other important fields of Analytical Chemistry. Future directions point toward the development and refinement of truly self-contained portable p-TAS devices that can be used for point-of-care or on-site analysis. It is foreseeable that in the near future these devices could be routinely employed for the detection of numerous clinically relevant compounds. 

Microfluidic devices have gained importance and utility for analyses of various molecules, including drugs and their metabolites. Vrouwe et al. [151] developed NCE for point-of-care testing of lithium in blood samples. The device consisted of a glass chip coupled with a conductivity detector. The authors tested this system for lithium analysis in five patients in the hospital. Furthermore, the authors reported that sodium, lithium, magnesium, and calcium were separated in <20 seconds. The authors claimed that the NCE system provided a convenient and rapid method for point-of-care testing of electrolytes in serum and whole blood. 

Blood for analysis may be obtained from veins, arteries, or capillaries. Venous blood is usually the specimen of choice, and venipuncture is the method for obtaining this speci-men. In young children and for many point-of-care tests, skin puncture is frequently used to obtain what is mostly capillary blood arterial puncture is used mainly for blood gas analyses. 

Halpern MT, Palmer CS, Simpson KN, Chesley FD, Luce BR, Suyderhoud JP, et al. The economic and clinical efficiency of point-of-care testing for critically iU patients a decision-analysis model. Am J Med Qual 1998 13 3-12. 

Statutory laws for driving under the influence of alcohol were originally based on the concentration of ethanol in venous whole blood. Because the collection of blood is invasive and requires intervention by medical personnel, the determination of alcohol in expired air has long been the mainstay of evidential alcohol measurements.There is also growing clinical interest m the determination of breath alcohol at the point-of-care. The fundamental principle for use of breath analysis is that alcohol in capillary alveolar blood rapidly equilibrates with alveolar air in a ratio... 

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