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Colorectal Surgery
Published in Tjun Tang, Elizabeth O'Riordan, Stewart Walsh, Cracking the Intercollegiate General Surgery FRCS Viva, 2020
Jennie Grainger, Samson Tou, Steve Schlichtemeier, William Speake, Fung Joon Foo, Frank McDermott
FIT stands for fecal immunochemical test. It is a type of FOB test, which uses antibodies that specifically recognise human haemoglobin. It utilises immunochromatography and uses antibodies that are specific for human haemoglobin. The test result is not influenced by non-human blood in feces. It will only react with the intact haemoglobin molecule, therefore should only identify pathology within the colon. This will reduce the number of false-positive results currently seen with the standard FOBT. The level of a ‘positive’ test, thus determining the need for a colonoscopy has yet to be finalised.In Scotland, FIT replaced guaiac-based FOB test for bowel screening in November 2017. FIT was rolled out in England and Wales as a replacement for FOBT in 2019.
Chikungunya Fever: Emergence and Reality
Published in Jagriti Narang, Manika Khanuja, Small Bite, Big Threat, 2020
Neelam Yadav, Bennet Angel, Jagriti Narang, Surender Singh Yadav, Vinod Joshi
The Centre for Disease Control (CDC) Atlanta has plotted a standard algorithm to understand the stage of infection. Serum samples of CHIKV-infected persons of less than 6 days can be investigated by real-time (RT) PCR assay, which employs particular primers. In addition to this, the infected serum sample of more than 6 days can be tested by Fpr antibodies using Mac-ELISA, and results have been confirmed by plaque reduction neutralization test (PRNT) assays (Johnson et al., 2016; Beaty et al., 1995; Lanciotti et al., 2006, 2014, 2016; Martin et al., 2000, 2004; Panning et al., 2009). Immunochromatographic (IC) assays are also being used for detecting viral infection.
Rapid Infectious Diseases Diagnostics in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Bronwen Garner, Kimberly Hanson
Detection of bacterial antigens in urine is a potentially rapid and non-invasive approach for evaluating suspected pneumonia. Bacterial cell wall components may translocate out of the lung parenchyma and into the bloodstream in the setting of invasive infection. Organism-derived proteins in the peripheral circulation are then filtered by the kidney and concentrated in the urine. Urine antigen tests (UATs) are immunoassays that use antibodies to capture and detect bacterial proteins. Immunoassays may be designed as enzyme immunoassays (EIAs) or lateral-flow immunoassays (LFAs). The latter are also referred to as immunochromatographic assays. Current UATs are designed to detect Legionella pneumophila and Streptococcus pneumoniae.
Strategies to improve the diagnosis and clinical treatment of dermatophyte infections
Published in Expert Review of Anti-infective Therapy, 2023
Immunochromatographic card tests are easy and rapid medical diagnostic tests with high sensitivity and specificity. In these low-cost tests, an additional device is often not needed, as the results of the analysis are visible to the naked eye. As sugar is used as the antigenic epitope in immunochromatographic card tests, the sensitivity of the test is high (83.5%), although the specificity is low (66.7%) [39]. When used for the first time in a study of the diagnosis of onychomycosis, the test had sensitivity and specificity of 85.4% and 58.3%, respectively [35]. In another study, both sensitivity (90.3%) and specificity (93.6%) were higher [40]. Taking the costs into consideration, in France, for example, the cost of direct microscopic examination is 6€; for fungal culture, 40€; for a 12-week terbinafine treatment, 90€; for PCR tests, 130€; and for immunochromatographic card tests, 20€. Therefore, immunochromatographic card tests are a cheaper and easier diagnostic method than PCR tests for rapid diagnosis in patients who cannot undergo direct microscopic examination.
The diagnostic methods in the COVID-19 pandemic, today and in the future
Published in Expert Review of Molecular Diagnostics, 2020
So Yat Wu, Hoi Shan Yau, Man Yee Yu, Hin Fung Tsang, Lawrence Wing Chi Chan, William Chi Shing Cho, Allen Chi Shing Yu, Aldrin Kay Yuen Yim, Marco J W Li, Yin Kwan Evelyn Wong, Xiao Meng Pei, Sze Chuen Cesar Wong
The principle of point-of-care-testing of antibody detection is similar to that of antigen testing, which is also based on immunochromatography. However, as summarized by Peaper and Landry (2014), additional buffer is required to bring the sample along the strip [37]. The antibody from the specimen first reacts with the labeled antigen in the conjugation pad, forming antigen-antibody-detector conjugate complexes, which will be captured by specific antibody in the test line, giving rise to a visible line [37]. A IgG-IgM combined antibody test of COVID-19 was developed by Jiangsu Medomics Medical Technologies. It detects anti-SARS-CoV-2 both IgM and IgG in blood specimen within 15 minutes with sensitivity and specificity of 88.66% and 90.63% respectively [51]. However, this study did not collect the clinical details of the patients like the stage of infection of the patients, as well as did not investigate into the interference of antibodies from other respiratory or coronavirus. It was demonstrated that the sensitivities and specificities of six commercially available POCT serological tests varies [47]. This study also revealed the cross-reactivity of negative antibodies with other human respiratory viruses and coronavirus, as well as suggested the detection efficiency of serological assays was higher than that of NAATs eight days after onset of symptoms.
Rapid and quantitative detection of urinary Cyfra21-1 using fluorescent nanosphere-based immunochromatographic test strip for diagnosis and prognostic monitoring of bladder cancer
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Qifang Lei, Linlin Zhao, Shuixian Ye, Yue Sun, Fangjie Xie, Hong Zhang, Fangjian Zhou, Song Wu
Cytokeratin 19 fragments (Cyfra21-1) is a soluble fragment of keratin CK19. Serum Cyfra21-1 is an effective diagnostic biomarker for cancers such as lung cancer and oral/oropharyngeal squamous cell carcinoma [10–12], and previous studies also confirmed that the diagnostic specificity and sensitivity of urinary Cyfra21-1 for bladder cancer were about 60–90% and 40–92%, respectively [8,13–16]. Immunoassay-based techniques such as electro chemiluminescent immunoassay, enzyme-linked immunosorbent assay (ELISA) and immunochromatographic assay were most often used for urinary Cyfra21-1 detection [17–19]. These detection methods suffer from some problems. The reaction system of chemiluminescence method is unstable, with complexity of the procedures and high instrument cost. The ELISA needs to pre-treat urine to extract protein so that the analysis time is relatively long. It is not suitable for rapid detection. Membrane-based lateral flow Immunochromatographic assay, often referred to as a point-of-care test, offers several advantages, such as rapidity, simplicity, selectivity and low cost. The colloidal gold is the most common type, but it can only be qualitative or semi-quantitative detection and cannot be used for trace analysis, it also occurs large false-negative rate because of the haematuria interference [20,21]. Therefore, there an increasing demand for improvement of immunochromatographic methods and to design new ones to achieve quantitative detection with great convenience, ideal sensitivity and specificity.