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Immunological Tests for Diagnosis of Disease and Identification of Molecules
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Antibody-coated latex beads can be used in agglutination or ELISA techniques to detect antigen in samples. In addition to simple tube or microtiter agglutination tests which are read visually, several devices have been developed for use of the principle of latex agglutination in tests that can be sold commercially and used by relatively untrained persons. Two tests using latex beads will be described: lateral flow immunoassay, an agglutination procedure, and vertical flow-through immunoassay, an ELISA procedure.
Screening Tests for HIV-1 Infection
Published in Niel T. Constantine, Johnny D. Callahan, Douglas M. Watts, Retroviral Testing, 2020
Niel T. Constantine, Johnny D. Callahan, Douglas M. Watts
Tests employing agglutination as the indicator system have been used for diagnosing infectious diseases for many years because they generally have good sensitivity for detecting antibody. However, specificity is sometimes compromised. Agglutination tests can incorporate a variety of antigen-coated carriers. Carriers are particles used to support or “carry” the antigen.
Immunoglobulins
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
Agglutination tests are often used to detect serum antibodies with a particular specificity. The specificity may be one normally present on the target cell, or it may not, in which case it is artificially coupled to a target cell, such as an erythrocyte. Serial dilutions of serum are mixed with target cells, and antibody levels are quantified as the highest dilution causing agglutination. Erythrocytes are often used in this technique, which is then called hemagglutination.
Overcoming challenges in the diagnosis and treatment of parasitic infectious diseases in migrants
Published in Expert Review of Anti-infective Therapy, 2020
Francesca F. Norman, Belen Comeche, Sandra Chamorro, Rogelio López-Vélez
Specific circulating anti-Leishmania antibodies are detectable in almost any immunocompetent individual with clinical VL but have a limited role in immunocompromised individuals. Serology may remain positive for many months after treatment and is therefore not useful for monitoring response to treatment and also has no use in cases of CL [78]. The most used quantitative serologic methods are direct agglutination tests, ELISA-based methods, and indirect immunofluorescence. The immunochromatographic strip using the rK39 antigen-RDT is a rapid qualitative diagnostic test which may be especially useful in migrants with infections acquired in specific geographical regions (97% sensitivity in the Indian subcontinent, 85% in east Africa, and 83% in the Mediterranean and Latin America) [86,87].
Current approaches to visceral leishmaniasis treatment in solid organ transplant recipients
Published in Expert Review of Anti-infective Therapy, 2018
Wanessa Trindade Clemente, Paulo Henrique Orlandi Mourão, Jose María Aguado
The definitive method for the confirmation of a diagnosis is the demonstration of parasites in the bone-marrow or in spleen aspirates. The sensitivity of microscopy varies from 53% to 86% in bone marrow aspirates and over 90% in splenic samples. Molecular techniques allow even greater sensitivity with the advantage of being less invasive procedures, as they can be performed using peripheral blood. Additionally, quantitative PCR can play an important role in monitoring the response to treatment. On the other hand, culture is time demanding, costly, and can take several weeks, limiting its impact on clinical decisions. The most widely used serological techniques are the indirect fluorescent antibody test, enzyme-linked immunosorbent assay (ELISA), and rapid tests, such as the immunochromatographic and direct agglutination tests. Sensitivity and specificity vary between the methods and antigens used. Antigens that are more specific, such as rK39, have been used in both ELISAs and rapid tests to improve the performance of these assays, but neither can be used for diagnostic confirmation in the absence of symptoms. Furthermore, serology assays should be supported by clinical correlation. In general, treatment is only recommended when the patient presents with a compatible clinical syndrome and laboratory evidence of VL [4–11].
Clinical management of women with listeriosis risk during pregnancy: a review of national guidelines
Published in Expert Review of Anti-infective Therapy, 2018
Lisa Pucci, Mario Massacesi, Giuseppina Liuzzi
Serological tests have long been considered unreliable tools for the diagnosis of listeriosis, since it lacks sensitivity as well as specificity [43,44]. Tests such as agglutination tests are not specific because of antigenic cross-reactivity between L. monocytogenes and other gram-positive bacteria, such as staphylococci and enterococci [45].