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Saturation Analysis: Radioimmunoassay and Other Ligand Assays
Published in Joseph Chamberlain, The Analysis of Drugs in Biological Fluids, 2018
The fluorescence polarization immunoassay technique has been shown to be reliable and specific for screening urine samples for drugs of abuse. In particular, it was claimed that herbal drinks could interfere with such assays, but this was refuted by the analysis of 50 such preparations which showed no interference with either the screening method using fluorescence polarization immunoassay or the confirmatory TLC method;1117 however, this study did not appear to investigate the urine of herbal tea drinkers. Table 8.3 lists a number of drugs for which fluorescence polarization immunoassay techniques have been developed.
Automation, Direct-Sample Analysis, and Microcolumn Liquid Chromatography
Published in Steven H. Y. Wong, Iraving Sunshine, Handbook of Analytical Therapeutic Drug Monitoring and Toxicology, 2017
Another major innovation in technology for DSA is the restricted access media (RAM). Two commercially available RAM are: the internal surface reversed phase (ISRP)29 and the shielded hydrophobic phase (HISEP),30 whereas another RAM, the dual zone media, was under development.31 ISRP, pioneered by Pinkerton, is a bimodal column support consisting of small-pore 52 Å silica gel with the hydrophobic peptide, glycine-phenylalanine-phenylalanine (GFF), bound to the internal surface of the pore, as shown in Figure 9–2. The bimodal chromatographic processes are the exclusion chromatography of the protein molecules as a result of the pore size and the reversed-phase hydrophobic interaction of drug molecules with GFF after migrating inside the pores. Figure 9–3 showed the DSA of phenobarbital and carbamazepine in serum by using ISRP column1 and other antiepileptics, such as phenobarbital and theophylline, may also be analyzed by ISRP. HISEP, another RAM for DSA, is also a bimodal column.30 The column support consists of a polymeric hydrophobic network of bonded polyethylene oxide, capable of excluding protein macromolecules, while drug and lower molecular weight analytes penetrate the network for hydrophobic interaction with the phenyl moiety. Phenobarbital was readily analyzed by direct injection of patient serum samples after centrifugation. The results correlated highly with those obtained by fluorescence polarization immunoassay.33
Comparison of a new enzymatic assay for serum homocysteine on Toshiba TBA-c16000 against an immunoassay on Abbott Architect
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2021
Prior to the development of mouse monoclonal antibodies, immunoassays were not the mainstream detection methods for Hcy analysis. Frantzen et al. introduced the technique of employing a monoclonal mouse anti-SAH antibody to measure the amount of SAH in a competitive enzyme immunoassay [17]. Without the use of radioisotopes and tedious chromatographic separation, this method allowed the development of an automated platform for Hcy analysis. The precision and correlation values of HPLC were acceptable. In addition, a fluorescence polarization immunoassay has been developed [18] and can be performed using an Abbott IMX analyzer (Abbott Park, IL). These methods facilitated the commercialization of Hcy assays, as most clinical laboratories have such equipment necessary to perform immunoassays. The use of a monoclonal antibody is the key to immunoassays, but it is also responsible for a major limitation of immunoassays due to additional antibody interactions in serum from patients receiving human anti-mouse antibody therapy or in those with heterophilic antibodies [19,20].
Mass spectrometry in emergency toxicology: Current state and future applications
Published in Critical Reviews in Clinical Laboratory Sciences, 2019
Xander M. R. Van Wijk, Robert Goodnough, Jennifer M. Colby
The proposed NACB tier 1 test menu makes use of qualitative screening for drugs-of-abuse (DOA) that can be performed by most hospital laboratories using standard immunoassays. These assays employ antibodies directed against specific drugs or drug classes and results can generally be produced in fewer than 60 min. Because the targets are small molecules, these assays are based on a competition principle, i.e. free drug in urine, or in some cases blood or saliva, competes with a labeled drug for a limited number of antibody binding sites. In the clinical laboratory, these tests are performed on automated chemistry analyzers and the most common methods are cloned enzyme donor immunoassay (CEDIA), enzyme multiplied immunoassay technique (EMIT), and DRI®, all of which produce color or NADH in an enzyme-mediated reaction if the free drug is present. Additional common methods include fluorescence polarization immunoassay (FPIA), where free drug reduces polarized fluorescence, and kinetic interaction of microparticles in solution (KIMS), where free drug reduces aggregation of microparticles.
A model based on machine learning for the prediction of cyclosporin A trough concentration in Chinese allo-HSCT patients
Published in Expert Review of Clinical Pharmacology, 2023
Lin Song, Chen-Rong Huang, Shi-Zheng Pan, Jian-Guo Zhu, Zong-Qi Cheng, Xun Yu, Ling Xue, Fan Xia, Jin-Yuan Zhang, De-Pei Wu, Li-Yan Miao
In all cases, CsA was given by intravenous administration. Generally, whole blood samples were drawn before the next dose twice per week. Electrochemiluminescence immunoassay analysis (ECLIA) performed on a Roche Cobas e411 analyzer (Roche Diagnostics GmbH, Mannheim, Germany) was used to detect CsA concentrations from May 2015 to December 2019. Fluorescence polarization immunoassay (FPIA) was performed on a TDx platform (Abbott, Chicago, USA), and chemiluminescent microparticle immunoassay (CMIA) was performed on the Architect R i1000SR platform (Abbott, Chicago, USA) after Dec 2019.