Principles of Immunochemical Techniques

Kricka, Larry J.; Phil., D.; Chem., C.; Park, Jason

doi:10.1016/b978-1-4160-6164-9.00016-0

Cited by 15 publications

(20 citation statements)

References 74 publications

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“…[14][15][16][17] All immunoassays incorporate either monoclonal or polyclonal antibodies that "capture" drugs and drug metabolites via a unique binding affinity for an epitope. The capture antibody thereby defines the specificity for a test.…”

Section: Immunoassaysmentioning

confidence: 99%

Demystifying Analytical Approaches for Urine Drug Testing to Evaluate Medication Adherence in Chronic Pain Management

McMillin¹,

Slawson²,

Marin³

et al. 2013

Journal of Pain & Palliative Care Pharmacotherapy

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This comprehensive review of analytical methods used for urine drug testing for the support of pain management describes the methods, their strengths and limitations, and types of analyses used in clinical laboratories today. Specific applications to analysis of opioid levels are addressed. Qualitative versus quantitative testing, immunoassays, chromatographic methods, and spectrometry are discussed. The importance of proper urine sample collection and processing is addressed. Analytical explanations for unexpected results are described. This article describes the scientific basis for urine drug testing providing information which will allow clinicians to differentiate between valid and questionable claims for urine drug testing to monitor medication adherence among chronic pain patients.

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Section: Immunoassaysmentioning

confidence: 99%

Demystifying Analytical Approaches for Urine Drug Testing to Evaluate Medication Adherence in Chronic Pain Management

McMillin¹,

Slawson²,

Marin³

et al. 2013

Journal of Pain & Palliative Care Pharmacotherapy

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“…Special IGE antibodies against cytotoxic-associated gene A (cag A) will be done in the sera of all patients with positive H.P positive antigen by ELISA method [15]. The kit (EUROIMMUN) recommends interpreting results as follow: …”

Section: Methodsmentioning

confidence: 99%

Helicobacter Pylori Infection: Association with Hashimoto’s Thyroiditis

Korani¹

2016

GHOA

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Autoimmune thyroid diseases (ATDS) are multifactorial conditions that result from genetic predisposition in combination with environmental risk factors. Helicobacter Pylori (HP) infection as an environmental risk factor has been proposed to initiate the antigenic components of the thyroid cell membrane and may play a leading role in the onset of the auto immune diseases such as Hashimoto's thyroiditis (HT).The Aim: To investigate the association between H.P infection and HT and the prevalence of cag. A positive strains H.P in the patients. Methods:The study include 40 female patients with Hashimoto's thyroiditis as a case group and 30 healthy female as control group. HP antigen in stool samples using unamplified enzyme immunoassay and Cag. Ainserum samples using an enzyme linked immunoassay method (ELISA). Anti-thyroid peroxidase antibodies (anti TPO) and thyroid function tests thyroid stimulating hormone (TSH) and thyroxine (T4) were determined. Results:There is statistically significant association between H P and HT (Odd ratio = 8.1, 95% confidence interval: 3-30.1, p<0.001). Also statistically significant association between presence of Cag-A positive strains of HP and HT (odd ratio=5.3, p=0.001). To establish the significant correlation between HP and HT further and more specialized studies are needed. Conclusion:There was a significant association between Hashimoto's thyroiditis and H.P infection and significant prevalence of cag. A positive strain of H.P positive patients and HT

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“…A variety of immunoassay methods are available, ranging from enzyme-linked immunosorbent assays (ELISAs) to homogeneous immunoassays that can be run on high-throughput analyzers commonly found in hospital clinical laboratories [3]. The most common alternative approach for measurement of steroid hormones is chromatography (especially high-performance liquid chromatography, HPLC), either alone or in combination with mass spectrometry (MS) (HPLC/MS or simply LC/MS) [4-7].…”

Section: Introductionmentioning

confidence: 99%

Cross-reactivity of steroid hormone immunoassays: clinical significance and two-dimensional molecular similarity prediction

et al. 2014

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BackgroundImmunoassays are widely used in clinical laboratories for measurement of plasma/serum concentrations of steroid hormones such as cortisol and testosterone. Immunoassays can be performed on a variety of standard clinical chemistry analyzers, thus allowing even small clinical laboratories to do analysis on-site. One limitation of steroid hormone immunoassays is interference caused by compounds with structural similarity to the target steroid of the assay. Interfering molecules include structurally related endogenous compounds and their metabolites as well as drugs such as anabolic steroids and synthetic glucocorticoids.MethodsCross-reactivity of a structurally diverse set of compounds were determined for the Roche Diagnostics Elecsys assays for cortisol, dehydroepiandrosterone (DHEA) sulfate, estradiol, progesterone, and testosterone. These data were compared and contrasted to package insert data and published cross-reactivity studies for other marketed steroid hormone immunoassays. Cross-reactivity was computationally predicted using the technique of two-dimensional molecular similarity.ResultsThe Roche Elecsys Cortisol and Testosterone II assays showed a wider range of cross-reactivity than the DHEA sulfate, Estradiol II, and Progesterone II assays. 6-Methylprednisolone and prednisolone showed high cross-reactivity for the cortisol assay, with high likelihood of clinically significant effect for patients administered these drugs. In addition, 21-deoxycortisol likely produces clinically relevant cross-reactivity for cortisol in patients with 21-hydroxylase deficiency, while 11-deoxycortisol may produce clinically relevant cross-reactivity in 11β-hydroxylase deficiency or following metyrapone challenge. Several anabolic steroids may produce clinically significant false positives on the testosterone assay, although interpretation is limited by sparse pharmacokinetic data for some of these drugs. Norethindrone therapy may impact immunoassay measurement of testosterone in women. Using two-dimensional similarity calculations, all compounds with high cross-reactivity also showed a high degree of similarity to the target molecule of the immunoassay.ConclusionsCompounds producing cross-reactivity in steroid hormone immunoassays generally have a high degree of structural similarity to the target hormone. Clinically significant interactions can occur with structurally similar drugs (e.g., prednisolone and cortisol immunoassays; methyltestosterone and testosterone immunoassays) or with endogenous compounds such as 21-deoxycortisol that can accumulate to very high concentrations in certain disease conditions. Simple similarity calculations can help triage compounds for future testing of assay cross-reactivity.

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Principles of Immunochemical Techniques

Cited by 15 publications

References 74 publications

Demystifying Analytical Approaches for Urine Drug Testing to Evaluate Medication Adherence in Chronic Pain Management

Demystifying Analytical Approaches for Urine Drug Testing to Evaluate Medication Adherence in Chronic Pain Management

Helicobacter Pylori Infection: Association with Hashimoto’s Thyroiditis

Cross-reactivity of steroid hormone immunoassays: clinical significance and two-dimensional molecular similarity prediction

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