Immunochemical testing

To our knowledge only one work has been reported on the use of a commercial immunochemical test to detect penicillins (penicillin G, penicillin V, ampicillin, cloxacillin, and oxacillin) in several environmental compartments. Thus, Campagnolo et al. [84] measured penicillin using the Charm IIRIA test in water samples proximal to a US farm. The LOD of the technique was 2 pg L L... 

In Waldenstrom macroglobulinemia the serum IgM value is invariably above 1000 mg/100 ml, and the serum should be diluted before any attempt is made to quantitate the IgM protein by immunochemical testing since antigen excess may obscure the precipitin ring and give falsely low results. 

In 1993, the incidence of antimicrobials in car tanker milk and the suitability of different tests for the detection of antimicrobials on the MRL level has been examined in Northern Germany using an integrated detection system (14). This system comprised microbial inhibitor tests for screening, immunochemical tests for preliminary confirmation, and high-performance liquid chromatography (HPLC) for final confirmation either in a parallel or a subsequent fashion in case of positive or questionable screening results. 

Currently, a number of immunochemical tests are commercially available in a kit format for many drugs. The 96-well plastic plate is one of the more commonly used formats of polystyrene and polyvinyl sold supports. It is well suited to automation and high throughput uses due to the wide variety of equipment that has been developed to simplify reagent transfer, rinsing steps, and interpretation of results. 

When the results obtained lie above the MRL, both qualification and quantification are becoming very important. Immunochemical tests that are often used for surveillance of registered drugs are prone to cross-reactions that may influence the result. It is therefore important to confirm and quantify the results of immunochemical methods with an independent physicochemical method. 

Apart from home-made methods, a number of quick, sensitive, and easy-to-perform immunochemical tests are currently available in a kit format. Table... 

Figure 11.30—Microplate rcculer. This device, indispensable for laboratories involved with immunochemical tests, is a spectrometer with an optical path that allows sequential absorbance measurements (for reaction kinetics) along the axis of each well of the microplate. (Multiscan instrument, reproduced by permission of Labsystems.)...

It is necessary to give some background information to understand the principle underlying immunochemical tests such as ELISA (Enzyme Linked Immuno Sorbent Assay). Such information is not always available to chemists, since chemistry and immunology have traditionally been separate disciplines. 

A radioisotope can be used as a tracer instead of the enzyme used in immunochemical tests. This method, introduced in 1960 for the measurement of insulin in serum, is called radio-immunology. It is the transposition in immuno-chemistry of the same principle as that used to determine the sulphate ion (cf. 17.5). Radioimmunoassays are similar to ELISA assays in the way in which the analysis is... 

Pullen et al. [192] have described a polychlorobiphenyl immunochemical test kit for soil analysis and showed that results corresponded well with those obtained from gas chromatographic electron capture detection. 

In closing this section we can state that the blood image areas appear to be composed of blood. Whether the blood is of human origin we cannot definitively say. However, we have recently confirmed the Italian immunochemical tests (22) suggesting that it is, in fact, human blood on the basis of positive tests involving human antiglobulin. Our tests em-... 

Jung K, Pergande M, Priem F, Becker S, IClotzek S. Rapid screening of low molecular mass proteinuria Evaluation of the first immunochemical test strip for the detection of tti-microglobulin in urine. Eur J Clin Chem Clin Biochem 1993 31 683-7. 

In summary, immunochemical testing is a highly sensitive, specific,... 

Zl. Ziccardi, R. J., and Cooper, N. R., Development of an immunochemical test to assess Cl-inhibitor function in human serum and its use for the diagnosis of hereditary an-giodema. Clin. Immunol. Immunopathol. 15, 465-471 (1980). 

Labelled antibodies with a fluorescent derivative obtained from fluorescein, rhodamine or luminarin, are well suited for the measurement of a number of human and animal immunoglobulins. However, the transposition of this principle to immunochemical testing for simple organic molecules remains, as yet, non-existent. There may be discrimination between the labelled and non-labelled species at the isolation stage for small organic molecules. This explains that only a few examples of analysis followed by fluorescence measurement. 

Johnson et al. (1973) first proposed the feasibility of application of an immunoassay method for the detection of insect pest contamination in food commodities. In their studies, crude extracts of individual insects such as D. melanogaster (eggs and adults), Plodia interpunctella (larvae), T. confusum (larvae), Ephestia elutella (larvae), S. oryzae (adults), and S. granarius (adults) served as antigens for the development of appropriate antibodies in rabbits. Subsequently, immunochemical tests comprising immunodiffusion and passive hemagglutination were conducted with insect extract samples to detect the pest. 

This study focused on the applicabili of the commercially availaUe immunochemical test kits to adequately screen for aflatoxin in cottonseed undw non-laboratoiy conditions by comparing their performance to laboratoiy results. On a obal e, TLC and immunochemical methods umuld have highest potential use. TLC was used to conflrm the presence and identity of aflatoxins in the test samples. 

Table 1. Comparison of Procedural Steps of Immunochemical Test IQts for Aflatoxin...

Ammoniated cottonseed samples were also analyzed in this study. Ammoniation is a process Aat has successfully reduced (>99%) aflatoxin levels in com, peanut and cottonseed products (1. Arizona uses ffiis process to treat aflamzin-contaminated, udiole cottonseed and cononsccd meal. This process had no apparent effect on the fiinction of any of die immunochemical test kits. 

Immunochemical tests (HemeSelect commercial kit) use an antihemoglobin antibody in a reverse passive hemagglutination procedure to detect the presence of human hemoglobin with a high degree of sensitivity. 

The human origin of a bloodstain can also be determined using the immunochemical test (Heme-Select commercial kit) and the immunochro-matographic test (Hexagon OBTI-test commercial kit) cited above. The latter is the most frequently used in forensic testing. 

The immunoglobulins present in the serum in the greatest amounts (IgG, IgA and IgM) can be measured by a variety of immunochemical tests using antiserum directed against one particular class of immunoglobulin (anti-IgG etc.). The techniques that can be used include radial immunodiffusion, automated immune precipitation and the Laurell rocket technique. Because of its much smaller concentrations, IgE is usually measured by radioimmunoassay. 

An immunochemical test, manufactured by Pharmacia, for the detection of specific IgE antibodies in allergic patients. A series of... 

---