I went last week to my doctor to ask for progesterone testing. I don't have the same concerns as you - my luteal phase seems to be an okay length, but I always have up to 6 days of brown spotting before AF, and several days after. While this could be normal for me, I read in numerous places, including TCOYF, that this could indicate a progesterone issue, and I wanted to get it checked out.
My doctor said she wasn't concerned about progesterone at this point, and wouldn't order a test for that. She did order a pelvic ultrasound to check for any lesions or cysts that could cause my spotting.
Wishing you the best of luck.