Estradiol also known as Estrogen LCMS
17-bêta-oestradiol Estradiol (17-ß-) (E2) via the more expensive LCMS method
is no longer available.
Liquid Chromatography - Tandem Mass Spectrometry'.
This one is not available anymore see as alternative: https://www.bloodtesting.nl/oestradiol-ook-bekend-als-oestrogeen.html
This Roche ECLIA estradiol has good agreement with the LCMS over the entire detection range.