Comparison of Methods to Measure Low Serum Estradiol Levels in Postmenopausal Women
Open Access
- 1 October 2006
- journal article
- research article
- Published by The Endocrine Society in Journal of Clinical Endocrinology & Metabolism
- Vol. 91 (10), 3791-3797
- https://doi.org/10.1210/jc.2005-2378
Abstract
Context: Accurate measurement of low serum estradiol (E2 < 30 pg/ml or < 110 pmol/liter) is needed to study relationships between endogenous E2 and risks of diseases in older women. Objective: The objective of this study was to determine whether an extraction-based (indirect) assay or a non-extraction-based (direct) assay correlates better with mass spectrometry and body mass index (BMI). Design/Setting: In a pilot study of 40 postmenopausal women, endogenous E2 measurements from three indirect and four direct assay methods and gas chromatography-tandem mass spectrometry (GC-MS/MS) were compared. A confirmatory study compared an indirect and a direct assay, selected among those in the pilot study, to GC-MS/MS; this study was conducted in 374 postmenopausal women not taking hormone therapy from the Ultra Low-dose TRansdermal estrogen Assessment (ULTRA) trial. Main Outcomes: Pearson correlation coefficients among E2 measurements by assay methods and BMI, and their confidence intervals, by bias-corrected bootstrap method, were used. Results: In the pilot study, E2 by three indirect assays correlated better (P < 0.03) with GC-MS/MS and with BMI than measurements by four direct assays. In the confirmatory study, the indirect assay correlated better (P < 0.01) with GC-MS/MS and BMI than the direct assay. Measurements by the indirect and direct assays were overestimated, but deviations in direct assay measurements were less precise. Mean E2 by the indirect and direct assays were higher (by 14 and 68%, respectively) and less reproducible than by GC-MS/MS. Conclusion: Until mass spectrometry is practical for wide use, extraction-based indirect assays may be preferable for measuring low postmenopausal serum E2.Keywords
This publication has 23 references indexed in Scilit:
- Endogenous oestrogens are related to cognition in healthy elderly womenClinical Endocrinology, 2005
- Sex Hormone Levels and Risk of Cardiovascular Events in Postmenopausal WomenCirculation, 2003
- Body Mass Index, Serum Sex Hormones, and Breast Cancer Risk in Postmenopausal WomenJNCI Journal of the National Cancer Institute, 2003
- Adiposity and Sex Hormones in Postmenopausal Breast Cancer SurvivorsJournal of Clinical Oncology, 2003
- Serum Estradiol Level and Risk of Breast Cancer During Treatment With RaloxifeneJAMA, 2002
- Serum Estradiol and Sex Hormone-Binding Globulin and the Risk of Hip Fracture in Elderly Women: The EPIDOS StudyJournal of Bone and Mineral Research, 2000
- Cognitive decline in women in relation to non-protein-bound oestradiol concentrationsThe Lancet, 2000
- Biochemical Markers of Bone Turnover, Endogenous Hormones and the Risk of Fractures in Postmenopausal Women: The OFELY StudyJournal of Bone and Mineral Research, 2000
- Elevated Serum Estradiol and Testosterone Concentrations Are Associated with a High Risk for Breast CancerAnnals of Internal Medicine, 1999
- Endogenous Hormones and the Risk of Hip and Vertebral Fractures among Older WomenNew England Journal of Medicine, 1998