Author
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Pantin Jackwood, Mary |
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WILLIAMS, SUSAN - University Of Georgia |
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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 3/31/2015 Publication Date: N/A Citation: N/A Interpretive Summary: Infectious agents or their constituent parts (antigens or nucleic acids) can be detected in fresh, frozen, or fixed tissues or other specimens, using a variety of direct or indirect assays. The assays can be modified to yield the greatest sensitivity and specificity but in most cases a particular methodology is chosen based on the nature of the sample, availability of equipment, quality of reagents, time, cost, and technical expertise. Bacteria, fungi, parasites or viruses can be visualized directly using light or electron microscopy. Although these procedures can be performed quickly, they are insensitive and require specialized equipment and technical support. Some tests such as agglutination reactions or immunodiffusion assays are simple and inexpensive but they can only be used to identify a particular etiologic agent possessing agglutinative or soluble antigens, respectively. Special histochemical stains can be inexpensive depending on the stain but can generate hazardous wastes that would need special disposal. The more cumbersome techniques such as antigen-capture enzyme-linked immunosorbent assays, immunohistochemical staining, or in situ hybridization offer increased sensitivity and specificity but require good quality reagents, additional pretreatment steps prior to testing, and a higher level of technical training. To optimize antigen detection systems for diagnostic and research purposes, it is important to become familiar with the limitations of the assays and to understand the pathogenesis of the suspected etiologic agent, to correctly select the timing and type of tissue samples for testing. Technical Abstract: Infectious agents or their constituent parts (antigens or nucleic acids) can be detected in fresh, frozen, or fixed tissues or other specimens, using a variety of direct or indirect assays. The assays can be modified to yield the greatest sensitivity and specificity but in most cases a particular methodology is chosen based on the nature of the sample, availability of equipment, quality of reagents, time, cost, and technical expertise. Bacteria, fungi, parasites or viruses can be visualized directly using light or electron microscopy. Although these procedures can be performed quickly, they are insensitive and require specialized equipment and technical support. Some tests such as agglutination reactions or immunodiffusion assays are simple and inexpensive but they can only be used to identify a particular etiologic agent possessing agglutinative or soluble antigens, respectively. Special histochemical stains can be inexpensive depending on the stain but can generate hazardous wastes that would need special disposal. The more cumbersome techniques such as antigen-capture enzyme-linked immunosorbent assays, immunohistochemical staining, or in situ hybridization offer increased sensitivity and specificity but require good quality reagents, additional pretreatment steps prior to testing, and a higher level of technical training. To optimize antigen detection systems for diagnostic and research purposes, it is important to become familiar with the limitations of the assays and to understand the pathogenesis of the suspected etiologic agent, to correctly select the timing and type of tissue samples for testing. |
