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Viral Infections
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Laboratory studies: The diagnosis is made clinically. This can be confirmed with a variety of studies, including polymerase chain reaction (PCR) testing, direct fluorescent antibody test (DFA), viral culture, serologies, and a Tzanck smear. Histopathologic evaluation shows intraepidermal vesicles with ballooning degeneration of multinucleate keratinocytes, acantholysis, and ground-glass inclusions.
Giardia
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Conventional microscopy is inexpensive and easy to perform, making it the method of choice for routine diagnosis in clinical laboratories with limited resources and equipment. However, this technique has a low to moderate sensitivity, is time consuming, and requires the skills of an experienced technologist to be performed and interpreted correctly. Shortage of competent microscopists is a pressing concern in many hospital and public health laboratories in industrialized countries.86,89 As a result, a number of alternative methods have been developed to overcome the limitations of light microscopy. Direct fluorescent antibody (DFA) assays are considered, together with PCR, the gold standard by many clinical laboratories. DFA methods use fluorescein-labeled antibodies directed against cell wall antigens of Giardia cysts to detect the parasite in stool samples with high sensitivity (96%–100%) and specificity (99%–100%).86,90,91 Commercial DFA tests are available, such as the widely used combos Crypto/Giardia-cel (Cel-labs, Sydney, Australia) and the Merifluor® Cryptosporidium/Giardia (Meridian Bioscience, Ohio). Although easy to perform, the main drawbacks of DFA are the relatively elevated cost of the required reagents (commercial kits) and equipment (fluorescence microscopy).
Bacterial Sexually Transmitted Diseases
Published in Attila Lorincz, Nucleic Acid Testing for Human Disease, 2016
Julius Schachter, Stephen A. Morse
The need (as well as the market) for diagnostic tests for these infections was so great that major manufacturers made efforts to develop nonculture diagnostic and screening tests. The first to be introduced were antigen detection methods such as direct fluorescent antibody (DFA) and enzyme immunoassays (EIAs). These were followed by direct nucleic acid hybridization assays4 that were rendered obsolete when the more sensitive NAATs became available.5 The NAATs have evolved and have become more sensitive. The ways in which NAATs are used continue to evolve; for example, we have seen an increased use of vaginal swabs as specimens. The U.S. Food and Drug Administration (FDA) recently cleared the use of vaginal swabs for screening with the APTIMA® Combo 2 test (Gen-Probe Inc., San Diego, California, USA).
A case of rheumatoid arthritis complicated with mucous membrane pemphigoid
Published in Modern Rheumatology Case Reports, 2021
Ryosuke Hanaoka, Toshiko Haginoya, Masami Koike
Biopsy of the oral mucosa revealed epidermal exfoliation, perhaps because the biopsy sample was taken from the base of the ulcer (Figure 3(A)). Lymphatic vessels located directly below the epidermis were enlarged and contained numerous neutrophils and few eosinophils centred around the capillaries, accompanied by severe infiltration of lymphoid and other small round cells (Figure 3(B,C)). Severe fibrosis of the dermis was also observed. The direct fluorescent antibody method was applied to a sample of the patient’s lip tissue. Complement component 3 (Figure 3(D)) and IgG (Figure 3(E)) deposits were seen in the epidermal basement membrane. The indirect fluorescent antibody method was also applied to a sample of the patient’s lip tissue. Normal mucosa was treated in 1 M saline for 48 h, and the dermis and epidermis were removed before adding serum from the patient, resulting in the appearance of linear deposits on the epidermis side (Figure 3(F)). Based on these findings, MMP was diagnosed.
The increasing importance of the novel Coronavirus
Published in Hospital Practice, 2021
Mohammad Ridwane Mungroo, Naveed Ahmed Khan, Ruqaiyyah Siddiqui
Samples collected can then be tested for the presence of SARS-CoV-2 through the common molecular diagnosis technique that relies on the sequence of nucleic acids for identification, known as polymerase chain reaction (PCR) [51]. Rapid and specific detection of SARS-CoV-2 with real-time reverse-transcription PCR can be performed using several sets of primers that have been established for detection of the virus [52]. While PCR is the main laboratory method used to detect SARS-CoV-2, other techniques have also been proposed. The use of Clustered regularly interspaced short palindromic repeats (CRISPR) technology as CRISPR has an ability to detect genetic snippets, has been suggested to detect SARS-CoV-2 [53]. Also, immunological methods including direct fluorescent antibody assay, immunofluorescence assay, semiconductor quantum dots, protein microarray, the microneutralization test and MAb-based rapid nucleocapsid protein detection can be used to rapidly detect SARS-CoV-2 [51]. In addition, Immunoassays, that comprise monoclonal antibodies to identify antigens of the virus or utilize virus antigens to distinguish patient antibodies instigated against the virus, have been utilized for recognition of SARS-CoV-2 [53]. A key feature of such immunoassays, particularly in the lateral assay set-up, is the capability to identify SARS-CoV-2 in less than 30 minutes without the need for trained personals or complex and expensive equipment.
An audit of inpatient stool ova and parasite (O&P) testing in a multi-hospital health system
Published in Journal of Community Hospital Internal Medicine Perspectives, 2020
Mohammad Qasim Khan, Nicole Gentile, Ying Zhou, Becky A. Smith, Richard B. Thomson, Eugene F. Yen
The labor-intensive nature of the traditional O&P exam, requiring a skilled technician, has led to the development of alternative methods of detecting fecal parasites. Direct fluorescent antibody tests, enzyme immunoassays, and immunochromatographic lateral flow assays, while more sensitive and specific than O&P exams, are available for only a limited number of organisms and are generally more expensive than direct microscopic examination [24]. As testing methods advance, laboratories will need to re-evaluate the availability of equipment, skill level of technicians, testing volume, test performance characteristics, specimen collection requirements and kit costs when deciding on the most ideal method to detect ova and parasites [24].