Hemagglutination assay sensitivity

Levine BB, Redmond AP, Fellner MJ, Voss HE, Levytska V (1966 a) Penicillin allergy and the heterogeneous immune responses of man to benzylpenicillin. J Clin Invest 45 1895 Levine BB, Fellner MJ, Levytska V (1966 b) Benzylpenicilloyl-specific serum antibodies in man. I. Development of a sensitive hemagglutination assay method and haptenic specificities of antibodies. J Immunol 96 707... 

H.Tamaki, N.Amino, Y.Iwatani, F.Matsuzuka, K.Kuma,and K.Miyai, Detection of thyroid microsomal and thyroglobulin antibodies by new sensitive radioimmunoassay in Hashimoto s disease Comparison with conventional hemagglutination assay, Endocrinol Japon 38 97(1991)... 

Methods for detection of anti-dsDNA include immunofluorescence, hemagglutination, radioimmunoassay (RIA), and enzyme-linked immunoassay (ELISA). Different methods may result in discrepant results due to the heterogeneous nature of the antibodies (S20). Numerous studies that compare methods conclude that no single test is perfect. It may be necessary to combine different methods for both higher sensitivity and higher specificity. The most commonly used methods for detecting anti-dsDNA are the CLIF test, the Farr assay, and the ELISA test. 

Cost Effectiveness. As with the other advantages of immunochemical analysis, cost may be quite variable. Reagent costs for several automated systems have been estimated at under 1.25 per sample. The cost is obviously much lower for less sophisticated assay systems, especially if some reagents are prepared in house. A major consideration is the expense of new instrumentation. For dedicated or automated instrumentation for either RIA or ELISA procedures, the cost may be 50-100,000. However, most analytical laboratories already have the basic instrumentation needed for immunoassays. Moderate sensitivity can be obtained through the use of numerous procedures such as radial immunodiffusion and hemagglutination. These procedures require no expensive equipment or reagents and they may be very useful in areas where equipment acquisition or maintenance is a problem. 

The antibody-coated red cells are prepared as previously described. It is particularly important for this procedure that the indicator red cells are absolutely free of clumps. The sensitivity of coated cells can be assayed by reverse passive hemagglutination if, as in the model under consideration, the antigen is available in soluble form. The cells under study are washed in suitable tissue culture medium or other buffered solution and suspended at a concentration of 10 per milliliter in the same diluent to which serum has been added (usually 1% fetal calf serum). A small volume (50-100 /U.1) of the cell suspension is placed in a 10 x 75 mm disposable tube. The addition of an equal volume of 1% coated red cells results in a mixture that contains about 25 red cells per lymphocyte. Linkage of antibody on the red cells to the corresponding antigen determinant on the surface of the lymphocyte results in the formation of a rosette or lymphocyte surrounded by red cells. The mixing of cells and incubation for at least 1 hr are done in an ice bath. The tubes are then centrifuged very briefly (1 min at 1000 g), and a drop of dye is added to tint the lymphocytes (e.g., crystal violet or brilliant cresyl blue). The mixture is then aspirated four or five times with a Pasteur pipette and examined in a hemacytometer chamber at about 400 x. A cell is scored as a rosette if it is surrounded by three or more adherent erythrocytes, and usually 300 cells are counted. 

Several methods are available for measurement ofTPO-Ab in serum. Most early studies were done with assays based on immunoflourescence or passive tanned erythrocyte hemagglutination using crude thyroid microsomes as antigen, and the results were reported as positive or negative or as an antibody titer. After identification of TPO as the microsomal antigen, more sensitive methods for detecting TPO-Ab have been established, including RIA, IRMA, ELISA and chemiluminescence methods (Dherbomez... 

Serologic assays measuring the immune response to plague infection are mainly of value retrospectively, since patients present clinically before they develop a significant antibody response. Enzyme-linked immunosorbent assay (ELISA) tests and the older, less-sensitive passive hemagglutination as-... 

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