A purification step prior to commercial sensitive immunoassay is necessary to achieve clinical usefulness when quantifying serum 17β-estradiol in prepubertal children

ObjectiveTo test the clinical usefulness of sensitive commercial immunoassays for determination of low 17β-estradiol concentrations in children.MethodsThe lower limit of detection and clinical usefulness (functional sensitivity) of three commercial estradiol immunoassays were validated by use of 500...

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Bibliographic Details
Published in:European journal of endocrinology 2008-01, Vol.158 (1), p.117-124
Main Authors: Ankarberg-Lindgren, Carina, Norjavaara, Ensio
Format: Article
Language:English
Subjects:
Biological and medical sciences
Clinical Studies
Endocrinopathies
Fundamental and applied biological sciences. Psychology
General aspects
Medical sciences
Vertebrates: endocrinology
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Summary:ObjectiveTo test the clinical usefulness of sensitive commercial immunoassays for determination of low 17β-estradiol concentrations in children.MethodsThe lower limit of detection and clinical usefulness (functional sensitivity) of three commercial estradiol immunoassays were validated by use of 500 sera from prepubertal and pubertal children and 55 pooled sera. The three immunoassays consisted of two modified direct immunoassays; one RIA (Spectria Estradiol RIA) and one time-resolved fluoroimmunoassay (AutoDELFIA Estradiol), both with increased serum volume in relation to antibody concentration and extended incubation time. In the third method, serum was purified and concentrated using diethyl ether extraction prior to measurement by the modified Spectria Estradiol RIA.ResultsThe lower limits of detection and clinical usefulness were 9 and 30 pmol/l for the direct RIA, 11 and 50 pmol/l for the AutoDELFIA, and 4 and 6 pmol/l for serum determined by extraction RIA. When measuring the serum pool originating from girls at breast stages 1–2, the direct RIA and AutoDELFIA resulted in significantly higher 17β-estradiol concentrations when compared with the extraction RIA (+58 and +267%, P
ISSN:0804-4643
1479-683X
DOI:10.1530/EJE-07-0403