Oestradiol assays: fitness for purpose?

Abstract

In this review we discuss the analytical inadequacies of oestradiol assays in relation to the clinical requirements for performing them, and make recommendations for their improvement. The measurement of oestradiol can be requested in a number of clinical scenarios ( precocious puberty, infertility, assisted conception, hormone replacement therapy). The very wide dynamic range of oestradiol concentrations is a huge challenge for routine assays, which they are unlikely to meet on theoretical as well as practical grounds. The EQA performance of oestradiol assays in terms of trueness, comparability, recovery and analytical sensitivity leaves much to be desired and indicates that calibration is compromised by poor analytical specificity. To make oestradiol assays fit for purpose requires concerted action by all stakeholders to define analytical quality specifications for the various clinical scenarios involved, and then to encourage concerted action by the diagnostic industry to use the steroid reference measurement system to improve specificity, trueness and traceability.

Performance of Direct Estradiol Immunoassays with Human Male Serum Samples

“…On the basis of measurements of this reference panel, each immunoassay deviated significantly from the reference LC-MS method throughout the working range, with the magnitude of positive (upward) bias varying between assays from 6% to 74%. As the variability seen here is based on single versions of each assay, a significantly greater variability might be expected when interlaboratory variability is included (26 ). It is possible that the immunoassays are able to separate concentrations within reference intervals from clearly increased serum E 2 in men; however, method-dependent reference intervals would be required.…”

“…This reflects generational improvement over less analytically sensitive previous E 2 immunoassays (13 ). Replicate imprecision was better with most platform E 2 immunoassays owing to the use of automated rather than manual pipetting; however, the most accurate direct E 2 immunoassay had replicate imprecision inferior to that of LC-MS, a longrecognized limitation of E 2 immunoassays (26 ). This presumably reflects the worse imprecision of immunoassays at the low end of their working range.…”

Mass spectrometry and immunoassay: how to measure steroid hormones today and tomorrow

“…Oestradiol " It has been known for many years that E 2 IA methods behave poorly for the measurement of samples from men, children and postmenopausal women (32). Achieving the necessary sensitivity using LC-MS/MS without resorting to complex derivatization methods has been a challenge but the discovery of using trace amounts of ammonium fluoride in the mobile phase has enabled the development of assays capable of measuring as low as 10 pmol/l (33,34), which is suitable for the vast majority of samples.…”

Development of a highly sensitive method for the quantification of estrone and estradiol in serum by liquid chromatography tandem mass spectrometry without derivatization

“…For concentrations below 20 pg/mL (74 pmol/L) correlation with concentrations measured with a reference GC-MS/MS method is very poor [6,10,11]. Although indirect immunoassays with extraction and chromatographic separation steps (e.g.…”