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Category: Clinical Microbiology
Immunoassays for the Diagnosis of Infectious Diseases * , Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap05-1.gif /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap05-2.gifAbstract:
This chapter summarizes the variety of different assays available and their particular application in the field of infectious diseases. The discussion emphasizes general assay design, with important caveats relevant to test interpretation and development. The first immunoassays available measured milligram to microgram quantities of antibodies and relied primarily upon precipitation reactions between antigen and antibody. There are many classic agglutination assays used in the diagnosis of infectious diseases, such as the Widal test for typhoid fever. The spectrum of immunologic assays is discussed in detail. Enzyme immunoassays (EIAs) can be broadly classified as either homogeneous or heterogeneous assays. Noncompetitive indirect solid-phase ELISA is one of the most frequently employed immunoassays in a clinical laboratory. There are various types of anti-animal antibodies; the most commonly reported are human anti-mouse antibodies (HAMA). There are many different assay designs which combine an array of technologies, including chemiluminescence (CL), fluorescence immunoassay (FIA), flow cytometry, and molecular diagnostics (PCR and use of oligonucleotides and nanoparticles). As these assays provide rapid results and can be performed with very small sample sizes, they have wide applicability to epidemiological studies and vaccine trials. These assays are also especially suited to the assessment of multiple biological agents in a variety of samples.
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Direct and indirect IFAs.
Direct and indirect IFAs.
Competitive EIA. Ab, antibody.
Competitive EIA. Ab, antibody.
Noncompetitive indirect solid-phase ELISA.
Noncompetitive indirect solid-phase ELISA.
IgM capture assay.
IgM capture assay.
Western blot procedure.
Western blot procedure.
Principle of IPCR. (a) DNA directly conjugated to reporter antibody; (b) DNA conjugated via an avidin-biotin reaction.
Principle of IPCR. (a) DNA directly conjugated to reporter antibody; (b) DNA conjugated via an avidin-biotin reaction.
Lateral-flow immunoassay.
Lateral-flow immunoassay.
Sensitivities of immunoassays a
a Data from references 24 and 46 .