Hormone replacement therapy (oestradiol-only preparations): can the laboratory recommend a concentration of plasma oestradiol to protect against osteoporosis?

Abstract

Target concentrations of plasma oestradiol to protect against osteoporosis have now been published in at least one textbook 1 and are increasingly discussed by clinicians. A survey of the literature revealed that many reports do not give details of oestradiol assay methods, despite the fact that there is a wide range of biases. Plasma oestradiol measurements made after ingestion of equine oestrogen preparations are not valid, and for oral oestradiol and oestradiol valerate preparations a single untimed sample does not give a reliable estimate of the average exposure over 24 h. Oestradiol measurements in plasma from women using patch, gel or implant preparations could be useful provided that consideration is given to the time of sampling and to the assay method used, although target levels have not been established. Further studies are required in this area.

Oestradiol assays: fitness for purpose?

“…It is recommended that concentrations are measured three-monthly over the 12 months following the first implant and annually following subsequent implant. 25 …”

“…26 The data we have presented show that there are large differences in bias between the various methods that could potentially lead to mistreatment of patients if not taken into account when setting target concentrations. 25 Analytical system specification and tendering by laboratories uncertain. The established reference measurement system must be used to calibrate according to the scientific principles of metrological traceability.…”

“…The best time to sample is just before applying a new patch (trough level), the purpose being to confirm the adequacy of oestradiol replacement. 25 Oestradiol gels and nasal spray The value of monitoring oestradiol concentrations in these patients is still unclear.…”

“…The best time to sample is just before applying a new patch (trough level), the purpose being to confirm the adequacy of oestradiol replacement. 25…”

“…26 The data we have presented show that there are large differences in bias between the various methods that could potentially lead to mistreatment of patients if not taken into account when setting target concentrations. 25…”