Hello Dr., I have a question about which estrone test should be used with your E1 + E2 target of 40–100. I didn't know if the Estrone serum assay test or the LC/MC test were similar, so I just got both tests. In this case, just an example, The Estrone by LC-MS/MS was 17 pg/mL And yet, the Standard serum estrone by EIA was 81 pg/mL Given the large discrepancy between these two methods, I am not sure which one to use for the E1+E2 formula. Which estrone method did you intend for your formula: LC-MS/MS or the standard serum immunoassay? And for the estradiol I assume its LC-MS/MS? And I'm also curious to know about how these two tests can result in such different numerical amounts - if you have any insight behind that. Thank you