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Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin

BACKGROUND: Many diagnostic tests for insulin dysregulation use reference intervals established with an insulin radioimmunoassay (RIA) that is no longer available. A chemiluminescent immunoassay (CLIA) is commonly used for the measurement of serum insulin concentration in clinical practice but requi...

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Autores principales: Carslake, H.B., Pinchbeck, G.L., McGowan, C.M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5354037/
https://www.ncbi.nlm.nih.gov/pubmed/28124389
http://dx.doi.org/10.1111/jvim.14657
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author Carslake, H.B.
Pinchbeck, G.L.
McGowan, C.M.
author_facet Carslake, H.B.
Pinchbeck, G.L.
McGowan, C.M.
author_sort Carslake, H.B.
collection PubMed
description BACKGROUND: Many diagnostic tests for insulin dysregulation use reference intervals established with an insulin radioimmunoassay (RIA) that is no longer available. A chemiluminescent immunoassay (CLIA) is commonly used for the measurement of serum insulin concentration in clinical practice but requires further validation, especially at clinically relevant reference intervals. OBJECTIVES: To evaluate the CLIA for measurement of equine insulin and compare it to the previously validated, but now unavailable RIA. SAMPLES: Equine serum samples (n = 78) from clinical and experimental studies. METHODS: In this experimental study, performance of the CLIA was evaluated using standard variables, including comparison with the RIA. Continuous and binary outcomes were analyzed. RESULTS: The CLIA showed good intra‐assay (coefficient of variation [CV], 1.8–2.4%) and interassay (CV, 3–7.1%) precision. Acceptable recovery on dilution (100 ± 10%) was achieved only at dilutions <1:1. Recovery on addition was acceptable. Comparison of the CLIA and RIA showed strong positive correlation (r = 0.91–0.98), with fixed and proportional bias. At 3 diagnostic cutoffs, sensitivity of CLIA compared with RIA ranged from 67 to 100% and specificity from 96 to 100%. CONCLUSIONS AND CLINICAL IMPORTANCE: The CLIA is a highly repeatable assay which is suitable for within‐ and between‐horse comparisons. Dilution of high concentration samples should be performed with charcoal‐stripped serum (CSS) and at the lowest dilution factor possible. At concentrations commonly used for diagnosis of insulin dysregulation (≤100 μIU/mL), results from the CLIA tend to be lower than from the RIA and should be interpreted accordingly. Further standardization of equine insulin assays is required.
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spelling pubmed-53540372017-03-22 Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin Carslake, H.B. Pinchbeck, G.L. McGowan, C.M. J Vet Intern Med EQUID BACKGROUND: Many diagnostic tests for insulin dysregulation use reference intervals established with an insulin radioimmunoassay (RIA) that is no longer available. A chemiluminescent immunoassay (CLIA) is commonly used for the measurement of serum insulin concentration in clinical practice but requires further validation, especially at clinically relevant reference intervals. OBJECTIVES: To evaluate the CLIA for measurement of equine insulin and compare it to the previously validated, but now unavailable RIA. SAMPLES: Equine serum samples (n = 78) from clinical and experimental studies. METHODS: In this experimental study, performance of the CLIA was evaluated using standard variables, including comparison with the RIA. Continuous and binary outcomes were analyzed. RESULTS: The CLIA showed good intra‐assay (coefficient of variation [CV], 1.8–2.4%) and interassay (CV, 3–7.1%) precision. Acceptable recovery on dilution (100 ± 10%) was achieved only at dilutions <1:1. Recovery on addition was acceptable. Comparison of the CLIA and RIA showed strong positive correlation (r = 0.91–0.98), with fixed and proportional bias. At 3 diagnostic cutoffs, sensitivity of CLIA compared with RIA ranged from 67 to 100% and specificity from 96 to 100%. CONCLUSIONS AND CLINICAL IMPORTANCE: The CLIA is a highly repeatable assay which is suitable for within‐ and between‐horse comparisons. Dilution of high concentration samples should be performed with charcoal‐stripped serum (CSS) and at the lowest dilution factor possible. At concentrations commonly used for diagnosis of insulin dysregulation (≤100 μIU/mL), results from the CLIA tend to be lower than from the RIA and should be interpreted accordingly. Further standardization of equine insulin assays is required. John Wiley and Sons Inc. 2017-01-26 2017 /pmc/articles/PMC5354037/ /pubmed/28124389 http://dx.doi.org/10.1111/jvim.14657 Text en Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial (http://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle EQUID
Carslake, H.B.
Pinchbeck, G.L.
McGowan, C.M.
Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin
title Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin
title_full Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin
title_fullStr Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin
title_full_unstemmed Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin
title_short Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin
title_sort evaluation of a chemiluminescent immunoassay for measurement of equine insulin
topic EQUID
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5354037/
https://www.ncbi.nlm.nih.gov/pubmed/28124389
http://dx.doi.org/10.1111/jvim.14657
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