Are estradiol results determined by the tandem mass spectrometry assay clinically useful for children?

The new approach to measure steroids by mass spectrometry (MS)-based methods has attracted increased interest in the last few years. Kushnir and coauthors have developed a sensitive isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for serum estrogens. Recently, they reported reference materials for children. 1 The information is of high interest because MS-based methods together with extraction radioimmunoassay (RIA) and recombinant cell bioassay (RCBA) have been suggested to be the most sensitive and accurate assays for determining low concentrations of serum estrogens. super(2,3) To date, few articles have been published that describe serum estradiol (E sub(2)) concentrations for children determined by sensitive extraction RIA super(4-9) and sensitive RCBA. super(10-12) The article by Kushnir et al super(1) is the first to show E sub(2) concentrations for children determined by MS.