{"title":"Validation of the Randox colorimetric assays for serum copper and zinc.","authors":"Simon A Handley, Troy Wanandy, Louise Prentice","doi":"10.1177/00045632231208337","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Serum copper and zinc are measured to assess deficiency and toxicity. Atomic absorption spectrophotometry and mass spectrometry methods are expensive and require highly trained staff. Colorimetric assays are available from Randox which are inexpensive and can be automated. We validated serum copper and zinc colorimetric assays on the Binding Site Optilite analyser including comparison with flame atomic absorption spectrophotometry (FAAS) and inductively coupled plasma-mass spectrometry (ICP-MS).</p><p><strong>Methods: </strong>Accuracy, imprecision, lower limit of quantitation, and linearity were ascertained. The impact of triglycerides, bilirubin, nickel, and iron on assay performance was also investigated. Comparison of results from colorimetric analysis of patient and external quality assurance samples with those obtained by FAAS and ICP-MS was undertaken.</p><p><strong>Results: </strong>Intra-, and inter-assay imprecision was <9%. Serum copper and zinc assays were linear between 1.8-35.6 and 2.3-45.7 µmol/L, respectively. Agreement was good between colorimetry and FAAS (intercept = -0.7, slope = 1.04) and ICP-MS (intercept = 0.6, slope = 0.99) for serum copper in patients' samples. For serum zinc, agreement was poor between colorimetry and FAAS (intercept = 2.2, slope = 0.87) and ICP-MS (intercept = 1.9, slope = 0.98) in patients' samples. There was a poor concordance in assessment of hypozincaemia between colorimetry and FAAS/ICP-MS.</p><p><strong>Conclusion: </strong>The Randox colorimetric assay for serum copper on the Optilite is simple to perform, has a short analysis time, and measured concentrations compare well with FAAS and ICP-MS. Due to poor agreement with FAAS and ICP-MS, colorimetry is not suitable for the measurement of serum zinc.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"182-194"},"PeriodicalIF":2.1000,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Annals of Clinical Biochemistry","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1177/00045632231208337","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2023/10/19 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"MEDICAL LABORATORY TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Serum copper and zinc are measured to assess deficiency and toxicity. Atomic absorption spectrophotometry and mass spectrometry methods are expensive and require highly trained staff. Colorimetric assays are available from Randox which are inexpensive and can be automated. We validated serum copper and zinc colorimetric assays on the Binding Site Optilite analyser including comparison with flame atomic absorption spectrophotometry (FAAS) and inductively coupled plasma-mass spectrometry (ICP-MS).
Methods: Accuracy, imprecision, lower limit of quantitation, and linearity were ascertained. The impact of triglycerides, bilirubin, nickel, and iron on assay performance was also investigated. Comparison of results from colorimetric analysis of patient and external quality assurance samples with those obtained by FAAS and ICP-MS was undertaken.
Results: Intra-, and inter-assay imprecision was <9%. Serum copper and zinc assays were linear between 1.8-35.6 and 2.3-45.7 µmol/L, respectively. Agreement was good between colorimetry and FAAS (intercept = -0.7, slope = 1.04) and ICP-MS (intercept = 0.6, slope = 0.99) for serum copper in patients' samples. For serum zinc, agreement was poor between colorimetry and FAAS (intercept = 2.2, slope = 0.87) and ICP-MS (intercept = 1.9, slope = 0.98) in patients' samples. There was a poor concordance in assessment of hypozincaemia between colorimetry and FAAS/ICP-MS.
Conclusion: The Randox colorimetric assay for serum copper on the Optilite is simple to perform, has a short analysis time, and measured concentrations compare well with FAAS and ICP-MS. Due to poor agreement with FAAS and ICP-MS, colorimetry is not suitable for the measurement of serum zinc.
期刊介绍:
Annals of Clinical Biochemistry is the fully peer reviewed international journal of the Association for Clinical Biochemistry and Laboratory Medicine.
Annals of Clinical Biochemistry accepts papers that contribute to knowledge in all fields of laboratory medicine, especially those pertaining to the understanding, diagnosis and treatment of human disease. It publishes papers on clinical biochemistry, clinical audit, metabolic medicine, immunology, genetics, biotechnology, haematology, microbiology, computing and management where they have both biochemical and clinical relevance. Papers describing evaluation or implementation of commercial reagent kits or the performance of new analysers require substantial original information. Unless of exceptional interest and novelty, studies dealing with the redox status in various diseases are not generally considered within the journal''s scope. Studies documenting the association of single nucleotide polymorphisms (SNPs) with particular phenotypes will not normally be considered, given the greater strength of genome wide association studies (GWAS). Research undertaken in non-human animals will not be considered for publication in the Annals.
Annals of Clinical Biochemistry is also the official journal of NVKC (de Nederlandse Vereniging voor Klinische Chemie) and JSCC (Japan Society of Clinical Chemistry).