mum & hot flashes

[west end girl]

Hi , I wondered if anyone could help me ...
My mother has been on and off HRT over the past 8 or so years , she doesn't really want to take it ( she is not at the moment !! ) but she gets loads of hot flashes and it really gets her down .. When she goes to see her GP ( we are in the UK ) they just kinda say try a different tablet etc ... Is there any kind of test she could ask for ??? a blood test etc ??? so she could find out what hormone she is missing/has to much off etc ???

Any help would be appricated