I need advice, so confused.

Hello
Sorry if this is the wrong forum to post in but I was looking for more information about hormone tests. So I know you are supposed to get hormone test two weeks before your period but what if the days vary between two or three days? Also are there certain hormones you request to have taken for NBE or do they test all hormones?
Any help would be so much appreciated. I need to see a doctor for other things as well and I need to clear this up.
Thank you so much.