Challenges to the measurement of estradiol: an endocrine society position statement.

The objective of the study was to evaluate the current state of clinical assays for estradiol in the context of their applications. The participants were appointed by the Council of The Endocrine Society and charged with attaining the objective using published data and expert opinion. Data were gathered from published sources via online databases (principally PubMed, Ovid MEDLINE, Google Scholar), and the clinical and laboratory experience of the participants. The statement was an effort of the committee and was reviewed by each member. The Clinical Affairs Committee, the Council of The Endocrine Society, and JCEM reviewers reviewed the manuscript and made recommendations. The measurement of estradiol in biological fluids is important in human biology from cradle to grave. In addition to its centrality in sexual development, it has significant effects on skin, blood vessels, bone, muscle, coagulation, hepatic cells, adipose tissue, the kidney, the gastrointestinal tract, brain, lung, and pancreas. Alterations in its plasma concentration have been implicated in coronary artery disease, stroke, and breast cancer. Although modern immunoassays and liquid chromatography/tandem mass spectrometry-based methods for estradiol are reasonably well suited to the diagnosis and management of infertility (nonetheless, imprecision and method-to-method differences remain problematic), the very low concentrations that appear to be crucial in nonreproductive tissues are a separate and more difficult issue. Such levels of estradiol are too low to be routinely measured accurately or precisely, and further evolution of analytical methods and the way in which estradiol is standardized is needed.