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Testosterone Replacement, Low T, HCG, & Beyond
Testosterone and Men's Health Articles
Methodological considerations in determining sex steroids in children
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<blockquote data-quote="madman" data-source="post: 262070" data-attributes="member: 13851"><p><strong>Abstract </strong></p><p><strong></strong></p><p><strong>Objectives: </strong><em>In laboratory medicine, external quality assessment (EQA) schemes have become versatile tools for detecting analytical flaws. However, EQA schemes are lacking for pediatric sex steroid levels. <strong>We aimed to investigate the suitability of different estradiol and testosterone immunoassays in a pediatric setting in comparison with clinical liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays.</strong></em></p><p></p><p><strong>Methods: </strong><em>The study was conducted by staff and the advisory group on endocrinology at Equalis, the Swedish provider of EQA schemes for laboratory medicine. <strong>The test material consisted of five pooled serum samples from children who were either prepubertal or in puberty. Clinical laboratories enrolled in Equalis EQA schemes for estradiol and testosterone were invited to participate, as were clinical laboratories using LC-MS/MS-assays. Samples were analyzed by either routine immunoassays (n=18) or in-house LC-MS/ MS assays (n=3).</strong></em></p><p></p><p><strong>Results:</strong> <em>For estradiol, LC-MS/MS assays showed a high degree of conformity with interlaboratory coefficients of variation (CV) below 24.2 %. Reported levels were between 4.9 ± 1.2 and 33.9 ± 1.6 pmol/L (group mean ± standard deviation). The direct immunoassays had lower precision; their CVs were up to 81.4 %. Reported concentrations were between 25.3 ± 18.1 and 45.7 ± 19.4 pmol/L, an overestimation compared to LC-MS/MS. Testosterone LC-MS/MS also showed a high degree of conformity, CVs were below 13.4 %, and reported concentrations were from 0.06 ± 0.00 to 1.00 ± 0.11 nmol/L. The direct immunoassays had a larger discrepancy between results; CVs were up to 95.8 %. Concentrations were between 0.12 ± 0.11 and 0.85 ± 0.23 nmol/L.</em></p><p></p><p><strong>Conclusions:<em> For the safe diagnosis and determination of sex steroids in children, analysis with mass spectrometrybased methods is recommended.</em></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong>Conclusions </strong></p><p><strong></strong></p><p><strong>This study enabled the following general conclusions to be drawn from pediatric samples. </strong></p><p></p><p><em><strong>(1) </strong>Commercially available estradiol immunoassays are not suitable for diagnosis in children. </em></p><p><em></em></p><p><em><strong>(2) </strong>Commercially available testosterone immunoassays have an uncertainty of reproducibility in the low range that each individual user should consider. </em></p><p><em></em></p><p><em><strong>(3) For the safe diagnosis and determination of sex steroids in children, analysis with MS-based methods is recommended.</strong> </em></p><p><em></em></p><p><em><strong>(4)</strong> <strong>Every pediatric endocrinologist or laboratory scientist should be familiar with the principles and pitfalls of the sex steroid methods they use. </strong></em></p><p><em><strong></strong></em></p><p><em><strong>(5) </strong>To increase conformity of methods used for diagnostics in children, participation in an EQA scheme is highly recommended. </em></p><p><em></em></p><p><em>(6) We recommend that manufacturers of sex steroid CLIA tests and laboratories that analyze them advertise these tests as recommended for adults, not children. </em></p><p><em></em></p><p><em><strong>(7) Since reliable sex steroid quantitation in children requires extremely high expertise, collaboration between biomedical laboratory scientists and clinicians is highly advantageous.</strong></em></p></blockquote><p></p>
[QUOTE="madman, post: 262070, member: 13851"] [B]Abstract Objectives: [/B][I]In laboratory medicine, external quality assessment (EQA) schemes have become versatile tools for detecting analytical flaws. However, EQA schemes are lacking for pediatric sex steroid levels. [B]We aimed to investigate the suitability of different estradiol and testosterone immunoassays in a pediatric setting in comparison with clinical liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays.[/B][/I] [B]Methods: [/B][I]The study was conducted by staff and the advisory group on endocrinology at Equalis, the Swedish provider of EQA schemes for laboratory medicine. [B]The test material consisted of five pooled serum samples from children who were either prepubertal or in puberty. Clinical laboratories enrolled in Equalis EQA schemes for estradiol and testosterone were invited to participate, as were clinical laboratories using LC-MS/MS-assays. Samples were analyzed by either routine immunoassays (n=18) or in-house LC-MS/ MS assays (n=3).[/B][/I] [B]Results:[/B] [I]For estradiol, LC-MS/MS assays showed a high degree of conformity with interlaboratory coefficients of variation (CV) below 24.2 %. Reported levels were between 4.9 ± 1.2 and 33.9 ± 1.6 pmol/L (group mean ± standard deviation). The direct immunoassays had lower precision; their CVs were up to 81.4 %. Reported concentrations were between 25.3 ± 18.1 and 45.7 ± 19.4 pmol/L, an overestimation compared to LC-MS/MS. Testosterone LC-MS/MS also showed a high degree of conformity, CVs were below 13.4 %, and reported concentrations were from 0.06 ± 0.00 to 1.00 ± 0.11 nmol/L. The direct immunoassays had a larger discrepancy between results; CVs were up to 95.8 %. Concentrations were between 0.12 ± 0.11 and 0.85 ± 0.23 nmol/L.[/I] [B]Conclusions:[I] For the safe diagnosis and determination of sex steroids in children, analysis with mass spectrometrybased methods is recommended.[/I] Conclusions This study enabled the following general conclusions to be drawn from pediatric samples. [/B] [I][B](1) [/B]Commercially available estradiol immunoassays are not suitable for diagnosis in children. [B](2) [/B]Commercially available testosterone immunoassays have an uncertainty of reproducibility in the low range that each individual user should consider. [B](3) For the safe diagnosis and determination of sex steroids in children, analysis with MS-based methods is recommended.[/B] [B](4)[/B] [B]Every pediatric endocrinologist or laboratory scientist should be familiar with the principles and pitfalls of the sex steroid methods they use. (5) [/B]To increase conformity of methods used for diagnostics in children, participation in an EQA scheme is highly recommended. (6) We recommend that manufacturers of sex steroid CLIA tests and laboratories that analyze them advertise these tests as recommended for adults, not children. [B](7) Since reliable sex steroid quantitation in children requires extremely high expertise, collaboration between biomedical laboratory scientists and clinicians is highly advantageous.[/B][/I] [/QUOTE]
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Testosterone Replacement, Low T, HCG, & Beyond
Testosterone and Men's Health Articles
Methodological considerations in determining sex steroids in children
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