Diagnostic immunology

Diagnostic immunology is a collective term for a variety of diagnostic techniques that rely on the specificity of the bond between antibodies and antigenes. Diagnostic immunology is well-suited for the detection of even the smallest of amounts of (bio)chemical substances. Antibodies specific for a desired antigen can be conjugated with a radiolabel, fluorescent label, or color-forming enzyme and are used as a "probe" to detect it.

Examples

Well-known applications of this include immunoblotting, ELISA and immunohistochemical staining of microscope slides. The speed, accuracy and simplicity of such tests has led to the development of rapid techniques for the diagnosis of disease, microbes and even illegal drugs in vivo (of course tests conducted in a closed environment have a higher degree of accuracy). Such testing is also used to distinguish compatible blood types.

Immunologic Techniques

• Immunoassay. "A technique using antibodies for identifying or quantifying a substance. Usually the substance being studied serves as antigen both in antibody production and in measurement of antibody by the test substance".
  • Immunochromatographic assay. This includes lateral flow tests such as a home pregnancy test.
  • Immunoenzyme Techniques. "Laboratory techniques that involve the in-vitro synthesis of many copies of DNA or RNA from one original template."
    • Enzyme-Linked Immunosorbent Assay (ELIZA). "An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye."
  • Radioimmunoassay. "Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system."

Genetic Techniques

• Nucleic Acid Amplification Techniques. "Laboratory techniques that involve the in-vitro synthesis of many copies of DNA or RNA from one original template."
  • Polymerase Chain Reaction. "In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive."
• Nucleic Acid Hybridization or its newer term, DNA Probes
  • Branched DNA Signal Amplification Assay
  • Dot blot assays, Southern blot assays

See also

• Wikipedia:MeSH E01#MeSH E01.450.495 --- immunologic tests
• Medical technologist

External links

• Immunologic+diagnosis at the US National Library of Medicine Medical Subject Headings (MeSH)

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